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TROUBLESHOOTING - 1C- 7

90-816462 2-695

Engine Cranks Over But Will Not Start Or Is Hard To Start

Important Information

1. First, determine which engine system is causing

the problem. To make an engine run, basic com-
ponents fuel, spark (ignition), and compression
are required. If all three components are present,
the engine should run. If any one of the three are
missing, weak, or arriving at the wrong time the
engine will not run.

2. Determine if there is fuel present by looking down

the carburetor venturi while actuating throttle.
There should be a stream of fuel coming out of the
accelerator pump nozzles if the carburetor has
fuel.

3. Check ignition system operation. Remove coil

wire from tower on distributor cap. Hold coil wire
near ground and check for spark while cranking
engine over. Repeat procedure with spark plug
wires. If there is spark at the spark plug wires, re-
move the spark plugs and make sure they are cor-
rect type and heat range, and not fouled or
burned.

4. Run a compression check on engine to make

sure the engine is mechanically sound.

Breaker Points Ignition (No Spark)

Cause

Special Information

1. Moisture on ignition components

1. Distributor cap or spark plug leads arcing.

2. Battery, electrical connections, damaged wiring

3. Ignition switch

3. May run in start position and lose spark in the run

position.

4. Shift interrupter switch

5. Shorted tachometer

5. Disconnect tachometer and try again.

6. Ignition timing

6. May crank over hard, backfire, or try to run back

wards

7. Faulty ignition resistor wire or bypass wire

8. Ignition points improperly gapped, burned or dirty

9. Spark plugs

9. Fouled, burned, cracked porcelain

10. Spark plug wires

10. Faulty insulation, broken wires

11. Cracked or dirty distributor cap or rotor

12. Coil

13. Condenser

14. Shift interrupter switch

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Summary of Contents for 13

Page 1: ...13 Printed in U S A 90 816462 2 695 1995 Brunswick Corporation GM 4 Cylinder MARINE ENGINES ...

Page 2: ...90 816462 2 695 0 ...

Page 3: ...sults of each method We have not under taken any such wide evaluation Therefore anyone who uses a service procedure and or tool which is not recommended by the manufacturer first must completely satisfy himself that neither his nor the product s safety will be endangered by the ser vice procedure selected All information illustrations and specifications con tained in this manual are based on the l...

Page 4: ...of parts sub jected to salt water and possibly complete failure of the engine Use of parts other than recommended service re placement parts will void the warranty on those parts which are damaged as a result of the use of other than recommended replacement parts Replacement Parts WARNING Electrical ignition and fuel system components on MerCruiser Engines and Stern Drives are de signed and manufa...

Page 5: ...This Manual MODEL SERIAL NUMBER MCM 3 0L OC856451 And Above MCM 3 0L 3 0LX OC868143 And Above IMPORTANT Refer To Engine Identification Page 3A 7 NOTICE Refer To Appropriate Stern Drive Manual fof transom assembly and stern drive unit repair ...

Page 6: ...er 3 0L 3 0 LX 181 C I D SECTION 3 Engine A G M In Line SECTION 4 Electrical Systems A Starting System B Ignition System C Charging System D Instrumentation E Wiring Diagrams SECTION 5 Fuel System A Fuel Pump B MerCarb 2 Barrel SECTION 6 Cooling and Exhaust A Seawater Cooled Models B Closed Cooled Models C Exhaust Manifolds Elbows SECTION 7 Power Steering A Power Steering ...

Page 7: ...1 A IMPORTANT INFORMATION GENERAL INFORMATION 72000 ...

Page 8: ...1A 3 Engine Identification 1A 3 Propeller Information 1A 3 Water Testing New Engines 1A 4 Page Boat And Engine Performance 1A 4 Boat Bottom 1A 4 Marine Fouling 1A 5 Weight Distribution 1A 6 Water In Boat 1A 6 Elevation And Climate 1A 6 NOTICE For information and procedures on trouble shooting refer to SECTION 1C NOTICE Refer to appropriate Stern Drive Service Man ual for transom assembly and stern...

Page 9: ... it is suggested that the procedure first be read through to gain knowl edge of the methods and tools used and the cautions and warnings required for safety How to Use This Manual This manual is divided into sections which represent major components and systems Some sections are further divided into parts which more fully describe the component Sections and section parts are listed on the Service ...

Page 10: ...e Balanced Shaft etc 2 What parts are included with a certain part Notice how the Description of Part for Ref Nos 1 and 10 through 13 are at the left side of the column Description of Part for Ref Nos 2 thru 9 are indented under Cylin der Block If Ref No 1 Cylinder Block was ordered all indented parts Ref Nos 2 thru 9 would come with the part Ref Nos 10 thru 14 would not come with Ref No 1 and wou...

Page 11: ...TION 3A for engine block identification Propeller Information Refer to the Propeller section in appropriate Mer Cruiser Stern Drive Service Manual or order publica tion 90 86144 What You Should Know About Quick silver Propellers Changing diameter pitch or coupling of a propeller will affect engine RPM and boat performance The blade configuration also will affect performance Two like propellers sam...

Page 12: ...o run above the specified RPM limit will cause excessive wear on internal engine parts which will lead to premature engine failure Water Testing New Engines Use care during the first 20 hours of operation on new MerCruiser engines or possible engine failure may occur If a new engine has to be water tested at full throttle before the break in period is complete follow this procedure 1 Run boat up o...

Page 13: ...icals min erals and other pollutants In salt water barnacles moss and other marine growth often produce dramat ic build up of material quickly Therefore it is impor tant to keep the hull as clean as possible in all water conditions to maximize boat performance Antifouling paint if required may be applied to boat hull observing the following precautions IMPORTANT DO NOT paint anodes or MerCa thode ...

Page 14: ...rt In extreme rough water conditions the safety of the boat and passengers may be in jeopardy Water in Boat When a boat loses performance check bilge for wa ter Water can add considerable weight to the boat thereby decreasing the performance and handling Make certain that all drain passages are open for complete draining Elevation and Climate Elevation has a very noticeable effect on the wide open...

Page 15: ...1 B 50617 IMPORTANT INFORMATION MAINTENANCE ...

Page 16: ...oling System 1B 9 Maintaining Crankcase Oil Level 1B 9 Overfilled Engine Crankcase 1B 9 Page Checking Engine Oil Level Filling 1B 9 Changing Oil and Filter 1B 9 Maintaining Power Steering Pump Fluid Level 1B 10 With Engine Warm 1B 10 With Engine Cold 1B 10 Filling and Bleeding Power Steering System 1B 11 Maintaining Closed Cooling Coolant Level 1B 11 Flushing Cooling System 1B 11 Lubrication 1B 13...

Page 17: ...t check level W kl Power steering fluid check level W kl Stern drive unit oil check level Weekly Battery check level and inspect for damage Weekly Fuel pump sight tube check that no fuel is present Power trim pump oil check level Anodes inspect for erosion Drive belts all inspect condition and check tension Every 100 hours or 120 days whichev er occurs first Propeller shaft lubricate Saltwater Eve...

Page 18: ...se or damaged wiring S l E h d Continuity circuit check components for loose connections broken or frayed wires Saltwater Every 50 hours or 60 days whichever occurs first Shift throttle cables and linkages lubricate and inspect for loose damaged or missing parts whichever occurs first Freshwater Every 100 or once yearly whichever occurs first Cooling system hoses and clamps inspect for damage and ...

Page 19: ... Ground Min Battery Cold Cranking Amperes 375 cca 475 mca 90 Ah Firing Order 1 3 4 2 Spark Plug Type AC MR43T Champion RV15YC4 NGK BR6FS AC MR43LTS Champion RS9YC NGK BPR6EFS Spark Plug Gap 035 In 0 9 mm Ti i Idl RPM Breaker Points Ignition 8 BTDC Timing at Idle RPM DDIS Ignition 8 BTDC Delco EST Ignition 1 BTDC NOTE Preliminary Idle Mixture 1 1 4 Turns Thermostat 143 F 62 C Dwell 39 45 Breaker Po...

Page 20: ...res MCM Stern Drive Model All Models Crankcase Oil1 with filter 4 U S Qts 3 8 L Seawater Cooling System2 9 U S Qts 3 8 L Closed Cooling System 9 U S Qts 8 5 L 1 Always use dipstick to determine exact quantity of oil required 2 Seawater cooling system capacity information is for winterization use only ...

Page 21: ...extend the life of your MerCruiser power package the following recommendations should be considered Use a propeller that allows the engine to operate at or near the top of the maximum RPM range See Specifications when at full throttle with a normal boat load Operation at 3 4 throttle setting or lower is recom mended Refrain from prolonged operation at maximum full throttle RPM 20 Hour Checkup Afte...

Page 22: ...thanol may cause in creased Corrosion of metal parts Deterioration of elastomer and plastic parts Fuel permeation through flexible fuel lines Wear and damage of internal engine parts Starting and operating difficulties Some of these adverse effects are due to the tenden cy of gasolines containing alcohol to absorb moisture from the air resulting in a phase of water and alcohol separating from the ...

Page 23: ...age common to boats create unique problems In cars gasoline alcohol blend fuels normally are consumed before they can absorb enough moisture to cause trouble but boats often sit idle long enough for phase separation to take place In addition internal corrosion may take place during storage if alcohol has washed protective oil films from internal components WINTER STORAGE If boat is to be placed in...

Page 24: ...t been run within 6 months replace ment of partial engines or after rebuilding an en gine Tools Required 71089 91 52024A1 Remote Starter Switch 1 Fill crankcase to proper level with recommended engine oil 2 Remove spark plugs 3 Leave ignition Key in OFF position 4 Connect remote starter switch to large 12V termi nal RED battery cable and small terminal YEL LOW RED wire on starter motor a If Remote...

Page 25: ...be if setting at rest in the water Allow sufficient time for oil to drain into the crank case if engine has just been run or oil has just been added Checking Engine Oil Level Filling IMPORTANT ENGINE CRANKCASE OIL MUST BE CHECKED AT INTERVALS SPECIFIED IN MAINTENANCE SCHEDULE CHART It is nor mal for an engine to use a certain amount of oil in the process of lubrication and cooling of the en gine T...

Page 26: ...silver Power Trim and Steering Fluid or automatic transmission fluid ATF Dexron or Dexron II through fill cap opening to bring level up to FULL HOT mark on dipstick DO NOT OVERFILL 5 If fluid is not visible in reservoir a leak exists in the power steering system Find cause and correct With Engine Cold 1 With engine stopped position drive unit so that it is straight back 2 Remove fill cap dipstick ...

Page 27: ...steering wheel back and forth to end of travel in each direction several times 5 Position drive unit so that it is straight back and stop engine Remove fill cap from pump Allow any foam in pump reservoir to disperse then check fluid level and add fluid as required to bring level up to FULL HOT mark on dipstick DO NOT OVERFILL Reinstall fill cap securely IMPORTANT Drive unit must be positioned stra...

Page 28: ...nings in gear housing b Connect hose between flushing attachment and water tap a 72012 b a Quicksilver Flushing Attachment b Garden Hose CAUTION If cooling system is to be flushed with boat in the water seacock if so equipped must be closed or water inlet hose must be disconnected and plugged to prevent water from flowing into boat 2 Partially open water tap s approximately 1 2 maximum capacity an...

Page 29: ...ow ing back into cooling system If boat is not fitted with a seacock water inlet hose must remain dis connected and plugged to prevent water from flowing into cooling system and or boat As a pre cautionary measure attach a tag to the ignition switch or steering wheel with the warning that the seacock must be opened or the water inlet hose reconnected prior to starting the engine a If equipped with...

Page 30: ...of operation or 30 days whichever com es first NOTE Operation in salt water is considered severe service 1 Check buzzer mounting screws heat switch and oil pressure switch for adequate tightness Tight en if loose but DO NOT over tighten 2 Check all wiring connections to be sure that they are tight and sealed where necessary Cold Weather or Extended Storage Precautions WARNING BE CAREFUL while work...

Page 31: ...ons to protect engine to lowest temperature to which it will be exposed DO NOT USE PROPYLENE GLYCOL antifreeze in closed cooling section Seawater section however must be drained completely CAUTION A discharged battery can be damaged by freez ing Layup NOTICE Refer to Cold Weather or Extended Storage Precautions in this section BEFORE proceeding 1 Fill fuel tank s with fresh gasoline that does not ...

Page 32: ...ctions Draining Seawater Raw Water Cooled Models NOTICE Refer to Cold Weather or Extended Storage Precautions in this section BEFORE proceeding 1 Engine must be as level as possible to ensure complete draining of cooling system 2 Remove drain plugs from cylinder block and man ifold 71424 a a Drain Plug Port and Starboard 3 Repeatedly clean out drain holes using a stiff piece of wire Do this until ...

Page 33: ... has been drained complete ly coat threads of drain plugs with Quicksilver Perfect Seal and reinstall Tighten drain plugs se curely Reconnect hoses and tighten all hose clamps securely If NOT equipped with sea cock seawater inlet hose must remain discon nected and plugged until engine is to be restarted IMPORTANT MerCruiser recommends that pro pylene glycol antifreeze nontoxic and biode gradable w...

Page 34: ... from exhaust manifold 71424 a a Drain Plug Port and Starboard 4 Remove aft rear drain plug from heat exchang er 71423 a a Drain Plug 5 If equipped with 3 in 76 mm or 6 in 152 mm risers remove drain plug as shown from riser 73175 a a Drain Plug Removed 6 Repeatedly clean out drain holes using a stiff piece of wire Do this until entire system is drained NOTE It may be necessary to lift bend or lowe...

Page 35: ...nnected prior to starting the en gine 10 After seawater section of cooling system has been drained completely coat threads of drain plugs with Quicksilver Perfect Seal and reinstall Tighten drain plugs securely Reconnect hoses and tighten all hose clamps securely If NOT equipped with seacock seawater inlet hose must remain disconnected and plugged until en gine is to be restarted Recommissioning N...

Page 36: ...1 C IMPORTANT INFORMATION TROUBLESHOOTING ...

Page 37: ... Inoperative 1C 13 Noisy Alternator 1C 14 Fuel System Rich 1C 14 Fuel System Lean 1C 15 Page Carburetor Malfunction 1C 15 Engine Runs Poorly At Idle 1C 16 Engine Acceleration Is Poor 1C 18 Engine Runs Poorly At High RPM 1C 19 Poor Fuel Economy 1C 20 Radio Noise 1C 21 Troubleshooting With Vacuum Gauge 1C 21 Miscellaneous 1C 22 Instrumentation Malfunction 1C 22 Engine Noise 1C 23 Important Informati...

Page 38: ...anual for all fuel line connections WARNING Make sure no fuel leaks exist before closing en gine hatch CAUTION DO NOT operate engine without cooling water be ing supplied to water pickup holes in gear hous ing or water pump impeller will be damaged and subsequent overheating damage may result CAUTION DO NOT operate engine without water being supplied to seawater pickup pump on engine or pump impel...

Page 39: ...pt covered to prevent foreign objects from entering combustion chamber Spark Plug Analysis Normal Condition Few deposits are present and probably will be light tan or gray in color This plug shows that plug heat range is compatible with engine and engine is electrically and mechanically in good running condi tion With proper plug servicing clean file and re gap this plug can be reinstalled with go...

Page 40: ...iming cooling system malfunction lean fuel air mixtures leaking intake manifold or sticking valves Replace spark plugs 72421 High Speed Glazing Insulator has yellowish varnish like color indicating that temperatures suddenly have risen usually dur ing hard fast acceleration under heavy load Nor mal deposits do not get a chance to blow off In stead they melt and form a conductive coating Replace pl...

Page 41: ...ode will show only normal wear Engine will misfire and idle rough To correct reverse primary coil leads Re place spark plugs 72422 Splashed Deposits Spotted deposits which sometimes occur after long delayed tune up accumulate after a long period of misfiring When normal combustion temperatures are restored upon installation of new plugs depos its loosen from top of piston and head and are thrown a...

Page 42: ...per drive unit trim angle B Propeller pitch too great C Dirty boat bottom marine growth D Poor running engine E Improper weight distribution F Rocker in boat bottom G False bottom full of water H Improperly adjusted trim tabs after planes 3 Propeller ventilating 3 A Drive unit installed too high on transom B Dirty or rough boat bottom C Damaged propeller pitch too small diameter too small D Keel l...

Page 43: ...n keel located too close to propeller and or too deep in the water ventilation Drive installed too high on transom wrong gear ratio 3 Operation 3 Unit trimmed out too far 4 Engine coupler slipping RPM Too Low Cause Special Information 1 Propeller 1 Damaged pitch too great diameter too great 2 Boat 2 Dirty or damaged bottom permanent or power hook in bottom false bottom full of water Drive installe...

Page 44: ...peat procedure with spark plug wires If there is spark at the spark plug wires re move the spark plugs and make sure they are cor rect type and heat range and not fouled or burned 4 Run a compression check on engine to make sure the engine is mechanically sound Breaker Points Ignition No Spark Cause Special Information 1 Moisture on ignition components 1 Distributor cap or spark plug leads arcing ...

Page 45: ...n sensor Is the engine harness power supply normal The ignition amplifier is defective Replace the motion sensor The ignition amplifier is defective Is the shift interrupter switch normal The engine harness battery ignition key ignition amplifier ground or other parts are defective Replace the ignition coil Repair or replace the shift interrupter switch Is the spark plug normal NO THE ENGINE FAILS...

Page 46: ...gnition amplifier is defective Is the shift interrupter switch normal Replace the ignition coil Repair or replace the shift interrupter switch Is the spark plug normal NO THE ENGINE FAILS TO IDLE YES YES Is spark plug wire good Replace spark plug wire YES NO NO Parts other than the DDIS are defective NO YES YES Reduce speed throttle setting see Overspeed Prevention Control 4B 12 MIS FIRE AT HIGH S...

Page 47: ... If the module is turned ON the voltage would be low but above 1 volt This could cause the ignition coil to fail from excessive heat With an open ignition coil primary winding a small amount of voltage will leak through the module from the BAT to the TACH terminal 5 Applying a voltage 1 5 to 8 volts to module termi nal P should turn the module ON and the tach terminal voltage should drop to about ...

Page 48: ...K VOLTS AT AND C TERMINALS OF DISTRIBUTOR HARNESS CONNECTION 1A 2 3 RECONNECT DISTRIBUTOR 2 TERMINAL CONNECTOR WITH IGNITION ON CHECK VOLT AGE FROM TACH TERMINAL TO GROUND BOTH TERMINALS 10 VOLTS OR MORE CHECK FOR OPEN OR GROUND IN CKT FROM C TERMINAL TO IGNITION COIL IF CKT IS OK FAULT IS IGNITION COIL OR CON NECTION UNDER 10 VOLTS C TERMINAL ONLY 4 REPAIR OPEN TACH LEAD OR CONNEC TION AND REPEAT...

Page 49: ...5 TO 8 V TO MODULE TERMINAL P CHART 1 OF 2 PAGE 11 LIGHT ON STEADY LIGHT BLINKS NO DROP IN VOLTAGE CHECK MODULE GROUND IF OK REPLACE MODULE CHECK FOR SPARK FROM COIL WIRE WITH TIMING LIGHT AS TEST LIGHT IS REMOVED FROM MODULE TERMINAL VOLTAGE DROPS 6 SPARK REPLACE IGNITION COIL AND REPEAT STEP 5 NO SPARK IS ROTATING POLE PIECE STILL MAGNETIZED SYSTEM OK IGNITION COIL REMOVED IS OK REINSTALL COIL A...

Page 50: ...safety switch 7 Open circuit 8 Starter solenoid 9 Starter motor 10 Mechanical engine malfunction Charging System Inoperative Cause Special Information 1 Loose or broken drive belt 2 Engine RPM too low on initial start 2 Rev engine to 1500 RPM 3 Loose or corroded electrical connections 4 Faulty battery gauge 4 Best way to test is to replace gauge 5 Battery will not accept charge 5 Low electrolyte o...

Page 51: ...el System Rich Cause Special Information 1 Warm engine carburetor percolation 1 Fuel boils out of float bowl when shut off and warm Floods intake manifold 2 Clogged flame arrestor 3 Automatic choke not opening 4 Float adjustment 5 Float leaks or is saturated with fuel 6 Needle and seat leaking 7 Carburetor gaskets leaking 8 Excessive fuel pump pressure 8 Unseats needle and seat 9 Cracked or porous...

Page 52: ...cap will act as a vent 6 Air leak on suction side of fuel system 6 Sucks air into fuel system reducing fuel volume 7 Plugged or pinched fuel line 8 Fuel pump 8 Low pump pressure Carburetor Malfunction Symptoms Cause 1 Flooding 1 A Needle and seat B Float adjustment C Saturated float D Gaskets leaking E Cracked fuel bowl F Fuel percolation G Automatic choke 2 Rough idle 2 A Idle RPM too low B Idle ...

Page 53: ...s D Leaking gaskets 6 Poor cold engine operation 6 A Idle RPM too low B Idle mixture screws C Throttle valves D Automatic choke E Engine flooding 7 Engine stalls 7 A Idle RPM too low B Idle mixture screws C Engine flooding D Automatic choke E Dirt in carburetor F Accelerator pump G Leaking gaskets 8 Hard starting 8 Refer to Engine Starts Hard Engine Runs Poorly At Idle Cause Special Information 1 ...

Page 54: ...urned cracked porcelain 10 Spark plug wires 10 Insulation breakdown wires broken 11 Defective coil 12 Cracked or dirty distributor cap 13 Incorrect float level 14 Dirty carburetor 15 Vacuum leak 15 Leak at manifold or carburetor base 16 Incorrect fuel pump pressure 16 Too low can t supply the carburetor Too high unseats the needle and seat 17 Low compression 17 Also check for blown head gasket 18 ...

Page 55: ...tor or amplifier advance curve 4 Refer to Section 4B 5 Accelerator pump 5 Check for stream of raw fuel from accelerator pump discharge nozzle when opening throttle with engine shut off 6 Cracked or dirty distributor cap or rotor 7 Vacuum leak 7 Intake manifold or carburetor base 8 Spark plugs 8 Fouled burned wrong heat range cracked porcelain 9 Float adjustment 10 Dirty carburetor 11 Low compressi...

Page 56: ...el tank vent 5 Fuel supply 5 Refer to Carburetor Malfunctions See Table of Contents 6 Ignition timing 7 Low grade of fuel or water in the fuel 8 Spark plugs 8 Fouled burned cracked porcelain incorrect heat range 9 Spark plug wires 9 Poor insulation broken wires 10 Distributor cap or rotor 10 Dirty or cracked 11 Coil 12 Distributor 12 Excessive play in shaft 13 Engine overheating 13 Refer to Engine...

Page 57: ...proper operating RPM at wide open throttle 4 Clogged flame arrestor 5 Engine compartment sealed too tight 5 Not enough air for engine to run properly 6 Boat bottom 6 Dirty marine growth hook rocker 7 Carburetor 7 Idle mixture settings accelerator pump adjust ments linkage binding choke adjustment carbu retor flooding over main fuel jets 8 Improper fuel 9 Crankcase ventilation system not working 10...

Page 58: ...ises 4 Accessories bilge pump bilge blower fish find er depth locator cabin heater motor etc Discon nect one at a time until noise disappears Troubleshooting With Vacuum Gauge Reading Cause 1 Steady reading between 15 21 inches at idle RPM 1 Normal 2 Extremely low reading but steady at idle RPM 2 Vacuum leak incorrect timing underpowered boat faulty boat bottom 3 Fluctuates between high and low at...

Page 59: ... grade or stale fuel 2 Water in fuel Instrumentation Malfunction Cause Special Information 1 Faulty wiring loose or corroded terminals 2 Faulty key switch 2 Test as outlined in SECTION 4D 3 Faulty gauge 3 Test as outlined in SECTION 4D 4 Faulty sender 4 Test As outlined in SECTION 4D ...

Page 60: ...er components Examples are flywheel or coupler exhaust flap pers rattling against exhaust pipe crankshaft striking pan pan baffle or dipstick tube rocker arm striking valve cover and loose flywheel cov er In many cases if this is found to be the problem a complete engine teardown is not necessary 6 When noise is isolated to a certain area and com ponent removal and inspection will be required Refe...

Page 61: ...in C Fuel Pump D Valve Lifter E Cam Bearings 2 Camshaft area center of engine timed to one half engine speed 2 A Fuel Pump B Valve Lifter C Cam bearing 3 Camshaft area rear of engine timed to one half engine speed 3 A Distributor gear B Valve lifter C Cam bearings 4 Camshaft area throughout engine timed to one half engine speed 4 A Loss of oil pressure B Valve lifters C Cam bearings ...

Page 62: ...D Rod bearing 2 Crankshaft area center of engine timed to engine speed 2 A Crankshaft striking pan or pan baffle B Main bearing C Rod bearing 3 Crankshaft area rear of engine timed to engine speed 3 A Loose flywheel cover B Loose coupler C Loose flywheel D Main bearing E Rod bearing 4 Crankshaft area throughout engine timed to engine speed 4 A Loss of oil pressure B Main bearings C Rod bearings ...

Page 63: ...cuum leak E Valve adjustment F Valve timing G Burned or stuck valve 3 Hissing 3 A Vacuum leak B Leaking exhaust manifolds or pipes C Loose cylinder heads D Blown head gasket 4 Whistle 4 A Vacuum leak B Dry or tight bearing in an accessory 5 Sparks jumping 5 A Leaking high tension lead B Cracked coil tower C Cracked distributor cap 6 Squeaks or squeals 6 A Drive belt slipping B Dry or tight bearing...

Page 64: ...ature warms up and engine is running at normal opening temperature it is normal for oil pressure to drop 6 Low engine oil pressure at idle 6 With modern engines and engine oils low oil pressure readings at idle do not necessarily mean there is a problem If valve lifters do not clatter at idle there is a sufficient volume of oil to lubri cate all internal moving parts properly The reason for the dr...

Page 65: ...ondensation 4 Oil pump 4 Relief valve stuck open pickup tube restricted worn parts in oil pump air leak on suction side of oil pump or pickup oil tube 5 Oil leak can be internal or external 5 Oil passage plugs leaking cracked or porous cyl inder block 6 Excessive bearing clearance 6 Cam bearings main bearings rod bearings High Oil Pressure Cause Special Information 1 Oil too thick 1 Wrong viscosit...

Page 66: ... Oil diluted or wrong viscosity 4 Oil level too high 5 Drain holes in cylinder head plugged 5 Oil will flood valve guides 6 Defective valve seals 7 Intake manifold gasket leaking 8 Worn valve stems or valve guides 9 Defective oil cooler if so equipped 9 Crack in cooler tubes 10 Defective piston rings 10 Glazed scuffed worn stuck improperly installed ring grooves worn improper break in wrong end ga...

Page 67: ...tering through the intake system exhaust sys tem or head gasket If the water is contained to crankcase only it is usu ally caused by a cracked or porous block a flooded bilge or condensation If the water is located in both the cylinder s and the crankcase it is usually caused by water in the cylinders getting past the rings and valves or com plete submersion Checking for rust in the intake manifol...

Page 68: ...over 4 Spark plug misfiring 4 Improper combustion causes moisture in the air to accumulate in the cylinder 5 Backwash through the exhaust system 6 Improper engine or exhaust hose installation 7 Cracked exhaust manifold 8 Improper manifold to elbow gasket installation 9 Loose cylinder head bolts 10 Blown cylinder head gasket 10 Check for warped cylinder head or cylinder block 11 Cracked valve seat ...

Page 69: ... restriction 8 Valve timing off 8 Jumped timing chain or improperly installed 9 Blown head gasket s 9 A blown head gasket s normally cannot be de tected by a compression check Normally the en gine will run at normal temperature at low RPM but will overheat at speeds above 3000 RPM Engines that are seawater cooled Using a clear plastic hose look for air bubbles between seawater pump and engine If t...

Page 70: ...y fail to prime or will force air bubbles into cooling system 5 Seawater inlet hose kinked or collapsed 6 Seawater pickup clogged 7 Obstruction on boat bottom causing water turbulence 7 Obstruction will be in front of seawater pickup causing air bubbles to be forced into cooling sys tem 8 Defective thermostat 9 Exhaust elbow water outlet holes plugged 10 Insufficient seawater pump operation 10 Wor...

Page 71: ...CTION 9A for bleeding procedure 4 Leaking hoses 4 Refer to SECTION 10A for bleeding procedure 5 Steering cables and or steering helm 5 Cable or helm partially frozen from rust or corrosion cable over lubricated improper cable installation 6 Binding in stern drive unit 6 Refer to appropriate Stern Drive Service Manual 7 Restriction in hydraulic hoses 7 Causes a loss of pressure 8 Control valve not ...

Page 72: ...es 6 Stop nut adjusted improperly 6 Refer to appropriate Stern Drive Service Manual 7 Steering cables installed that do not meet BIA standards 7 Refer to appropriate Stern Drive Service Manual Fluid Leaks Cause Special Information 1 Loose hose connections 1 Refer to SECTION 10A for bleeding instructions 2 Damaged hose 3 Oil leaking from top of pump 3 System overfilled fluid contains water fluid co...

Page 73: ...rowth on gear housing or boat bottom Engine will over heat while underway only 6 An object or an irregularity on boat or gear hous ing in area close to to water pick ups could create turbulence in water flow going to water pickups This could aerate the water flow and cause en gine to overheat 7 Stern drive installed too high on transom or drive unit trimmed out too far out allowing air to be drawn...

Page 74: ...2 A 50633 REMOVAL AND INSTALLATION 4 CYL ALPHA ONE DRIVE ...

Page 75: ... Specifications 2A 1 Tools Lubricants Adhesives Sealants 2A 1 Removal 2A 2 Engine Removal 2A 2 Installation 2A 5 Engine Installation Alignment 2A 5 Engine Connections 2A 8 NOTICE For information and procedures on troubleshooting refer to SECTION 1C 2A REMOVAL AND INSTALLATION ...

Page 76: ...Spline Grease 92 816391A4 Quicksilver 2 4 C Marine Lubricant With Teflon 92 825407A3 Quicksilver Liquid Neoprene 92 25711 2 Engine Alignment Tool 91 57797A3 91 805475A 1 Loctite Pipe Sealant with Teflon Obtain Locally CAUTION DO NOT use an alignment tool from another manufacturer Alignment tools other than Quicksilver Align ment Tools 91 805475A1 or a properly modified 91 57797A3 may cause imprope...

Page 77: ...er loosening clamp WARNING Be careful when working on fuel system Gaso line is extremely flammable and highly explosive under certain conditions Do not smoke or allow spark or open flame in area Wipe up any spilled fuel immediately 3 Disconnect and plug fuel line to prevent fuel in tank from leaking into bilge 50738 a b a Fuel Pump b Disconnect Fuel Inlet Line Here Plug inlet hose 4 Disconnect thr...

Page 78: ...t Assembly e Clevis Pin w Cotter Pin 6 Disconnect and cap power steering hoses plug control valve hose connection holes 50628 a b a Power Steering Control Valve b Power Steering Hoses 7 Loosen clamp and unplug wiring harness 50113 a c Breaker Point Ignition 50626 b c DDIS And EST Ignition Models a Engine Wiring Harness Receptacle Bracket b Instrumentation Wiring Harness c Hose Clamp ...

Page 79: ... 11 Disconnect seawater inlet hose from gimbal housing 22055 a b c a Water Tube b Hose Clamp Tighten Securely c Water Hose 12 Loosen hose clamps and disconnect exhaust el bow hose 13 Remove both shift cables from shift plate Retain locknuts and hardware 14 Disconnect any grounding wires and accessories that are connected to engine 50636 a a Ground Stud 15 Disconnect and suitably plug fluid hoses f...

Page 80: ... cemented in place on inner transom plate are present Inspect fi ber washers Replace if worn or damaged b Install double wound lockwashers onto inner transom plate inside fiber washer 72023 b c d a a Double Wound Lockwasher b Fiber Washer Cemented in Place c Inner Transom Plate Mount Engine Support d Locknuts Engine Mounting Bolts c Be certain rear engine mount locknuts are in position as shown d ...

Page 81: ...626 50633 b a a Center Lifting Eye DO NOT use to lift engine b Use This Lifting Eye 4 Align rear engine mounts with inner transom plate mounts while simultaneously aligning exhaust tubes with exhaust pipe hoses bellows 50629 c a b a Bellows b Clamps c Exhaust Pipe IMPORTANT Engine attaching hardware must be installed in sequence shown 5 Install both rear engine mounting bolts and hard ware as show...

Page 82: ...t to insert solid end of Quicksilver Alignment Tool through gimbal bearing and into engine coupler splines If it will not insert easily proceed to following b While observing the above precautions CAREFULLY raise and lower front of engine with hoist as required until tool will SLIDE FREELY all the way in and out of engine cou pler splines 70013 b a a Alignment Tool Use Only Quicksilver Alignment T...

Page 83: ...e moved 8 Tighten all exhaust system hose clamps securely as follows use two hose clamps on each connec tion 50633 a a Hose Clamps Engine Connections IMPORTANT When routing all wire harnesses and hoses be sure they are routed and secured to avoid coming in contact with hot spots on en gine and avoid contact with moving parts 1 Connect seawater hose to water tube at gimbal housing with hose clamp T...

Page 84: ...m gimbal housing to leads from engine harness 72992 b c d a a Brown White From Engine Harness b Black From Engine Harness c Black From Transom Assembly d Black From Transom Assembly WARNING Be careful when working on fuel system Gaso line is extremely flammable and highly explosive under certain conditions Do not smoke or allow spark or open flame in area Wipe up any spilled fuel immediately 4 Con...

Page 85: ...rd throttle lever end This will place a slight preload on cable to avoid slack in cable when moving remote control lever Adjust barrel on throttle cable to align with anchor stud c Secure throttle cable with hardware re tained as shown Tighten cable end guide locknut until it bottoms out and then back off one full turn Tighten cable barrel securely DO NOT OVER TIGHTEN as cable must piv ot freely 5...

Page 86: ...ons 22232 b c d a a ORANGE Wire From Electrode on Transom Assembly b RED PURPLE Wire Connect Other End to Positive Battery Terminal c BLACK Wire From Engine Harness d BROWN Wire From Electrode on Transom Assembly IMPORTANT Adjust shift cables as outlined in appropriate Stern Drive Service Manual 8 Refer to appropriate Stern Drive Service Manual and install and adjust drive unit and remote con trol...

Page 87: ...2026 b a a Large Fitting b Small Fitting Later Style Control Valve Torque fittings to 23 lb ft 31 N m 73786 10 Connect battery cables to battery by FIRST con necting POSITIVE battery cable usually RED to POSITIVE battery terminal Tighten clamp securely Then connect NEGATIVE battery cable usually BLACK to NEGATIVE battery terminal Tighten clamp securely NOTE Spray terminals with a battery connectio...

Page 88: ...3 A 26790 ENGINE 181 CID 3 0L 4 CYLINDER GM ENGINE ...

Page 89: ...linder Head 3A 16 Cleaning and Inspection 3A 16 Installation 3A 16 Cylinder Head and Valve Conditioning 3A 17 Disassembly 3A 17 Page Cleaning 3A 17 Inspection 3A 18 Rocker Arm Studs 3A 19 Valve Guide Bore Repair 3A 19 Valve Springs Checking Tension 3A 19 Valve Seats 3A 20 Reassembly 3A 20 Dipstick Specifications 3A 22 All Engines 3A 22 Oil Pan 3A 22 Removal 3A 22 Installation 3A 22 Oil Pump 3A 23 ...

Page 90: ...tallation 3A 37 Crankshaft Sprocket 3A 38 Removal 3A 38 Installation 3A 38 Page Camshaft 3A 38 Measuring Lobe Lift 3A 38 Removal 3A 39 Inspection 3A 39 Camshaft Gear Replacement 3A 40 Installation 3A 41 Camshaft Bearings 3A 42 Removal 3A 42 Inspection 3A 42 Installation 3A 42 Cylinder Block 3A 44 Cleaning and Inspection 3A 44 Cylinder Conditioning 3A 45 Cylinder Boring 3A 45 Cylinder Honing 3A 45 ...

Page 91: ...lock 21 28 Main Bearing Cap Bolts 65 88 Manifold to Head 23 Note 2 31 Oil Pan Bolts Crankcase 80 9 Oil Pan Bolts to Front Cover 45 5 Oil Pan Studs to Oil Seal Retainer or Crankcase 15 1 7 Oil Pump Cover 72 8 Oil Pump to Block 120 14 Oil Pump Pickup 60 7 Rocker Arm Cover and Bolts 40 4 5 Rear Crankshaft Oil Seal Retainer Nuts 135 15 Spark Plugs 22 30 Starter Motor to Block 37 50 Timing Gear Cover 7...

Page 92: ...Reamer 013 in oversize J8089 Carbon Remover Brush J5910 04 Piston Support Tool J24086 B Piston Pin Tool J3936 03 Piston Ring Groove Cleaner J8037 Piston Ring Compressor J5239 Connecting Rod Guide Tool 3 8 24 J8087 Cylinder Bore Checker J8369 Oil Pump Suction Pipe Installer J23042 B Timing Cover Seal Aligner J8520 Cam Lobe Lift Indicator J6098 01 Camshaft Bearing Installer Remover Tool J9534 01 Dis...

Page 93: ...ax PISTON RING COMPRESSION G Cl Production Top 0012 0029 0 030 0 073 Groove Clearance Production 2nd 0012 0029 0 030 0 073 Service 003 0 09 Max G Production Top 010 020 0 254 0 762 Gap Production 2nd 010 020 0 254 0 762 Service 035 0 88 Max PISTON RING OIL Groove C Production 001 006 0 026 0 152 Clearance Service Limit 007 0 17 Max Gap Production 010 030 0 254 0 762 Max Gap Service Limit 040 1 01 ...

Page 94: ... 002 0035 0 05 0 08 Crankshaft End Play 002 006 0 05 0 15 C k i Diameter 2 09980 20995 53 289 53 327 C k i Taper Production 0003 0 007 Max Crankpin Taper Service 001 0 02 Max Out of Round Production 0002 0 51 Max Out of Round Service 001 0 02 Max Rod Bearing C Production 0017 0027 0 044 0 0686 g Clearance Service Rod Size Clearance 006 017 0 153 0 4318 Max CAMSHAFT Lobe Lift Max Intake 2529 6 425 ...

Page 95: ...6 mm Seat Width Exhaust 1 16 5 64 0625 07812 in 1 6 2 0 mm S Production Intake 0010 0027 0 025 0 069 Stem Cl Production Exhaust 0007 0027 0 018 0 069 Clearance Service Intake 003 0 09 Max Service Exhaust 004 0 11 Max S i Free Length 2 1 16 in 52 mm S i Pressure Valve Closed 100 110 lb 136 149 N at 1 19 32 in 41 mm Spring Pressure Valve Open 208 220 lb 282 300 N at 1 7 32 in 31 mm p g Installed Hei...

Page 96: ...of the engine code stamped into the cylinder block This code number is stamped on all MerCruiser power packages and re placement partial engines but not replacement cylin der block assemblies If the engine serial number and or model decals are missing the engine code letters may help in deter mining the engine models 74520 a 3 0L uses the 2 5L cylinder head 3 0LX uses the 3 0L cylinder head a 4 Cy...

Page 97: ...cable and small terminal RED YELLOW wire on starter motor a If remote starter switch is not available dis connect PURPLE wire from ignition coil be fore using key switch to crank the engine over Tape terminal on PURPLE wire to prevent it from touching ground 5 Crank engine for 15 seconds then allow starter motor to cool down for 1 minute This should pre vent starter motor from overheating 6 Repeat...

Page 98: ...opposed by the pressure rise This can result in extensive damage to the internal parts from the high increase in combustion chamber temperature 72424 Pre Ignition Damage PRE IGNITION CAUSES 1 Hot spots in the combustion chamber from glow ing deposits due in turn to the use of improper oils and or fuels 2 Overheated spark plug electrodes improper heat range or defective plug 3 Any other protuberanc...

Page 99: ...ce is neglected OTHER CAUSES OF DETONATION IMPORTANT Use of improper fuels will cause en gine damage and poor performance 1 Over advanced ignition timing 2 Lean fuel mixture at or near full throttle could be caused by carburetor or leaking intake manifold 3 Cross firing spark plugs 4 Excess accumulation of deposits on piston and or combustion chamber results in higher compres sion ratio 5 Inadequa...

Page 100: ...er arm cover loose Gaskets which may adhere to cylinder head and rocker arm cover may be loosened by bumping end of rocker cover from the rear with palm of hand or a rubber mallet 3 Remove rocker arm cover Installation 1 Clean sealing surfaces on cylinder head and rocker arm cover with degreaser 2 Place new rocker arm cover gasket in position in rocker arm cover 3 Install rocker arm cover Torque s...

Page 101: ... reassembly in their origi nal locations Cleaning and Inspection 1 Clean parts with solvent and dry with compressed air 2 Inspect all contact surfaces for wear Replace all damaged parts Installation IMPORTANT When installing rocker arms and rocker arm balls coat bearing surfaces of rocker arms and rocker arm balls with engine oil 1 Install push rods in their original locations Be sure push rods se...

Page 102: ...rn Valve lash should be checked after engine has run and reached operating temperature 5 Crank engine one revolution until pointer 0 mark and torsional damper mark are again in align ment This is No 4 firing position With engine in this position the following valves may be ad justed No 2 Cylinder Exhaust No 3 Cylinder Intake No 4 Cylinder Exhaust 6 Install distributor cap spark plug wires and coil...

Page 103: ...bnormal stickiness b Galling or pickup between plunger and bore of lifter body usually caused by an abrasive piece of dirt or metal wedged between plung er and lifter body 2 Moderate rapping noise probable causes are a Excessively high leakdown rate b Leaky check valve seat c Improper adjustment 3 General noise throughout valve train this will in most cases be a definite indication of insufficient...

Page 104: ...ffed or worn inspect cylinder block lifter bore 4 If push rod seat is scuffed or worn inspect push rod Installation IMPORTANT It is recommended that the engine oil be changed and a new oil filter be installed whenever servicing valve lifters or camshaft IMPORTANT Before installing lifters coat the lift er with engine oil If new lifters or a new camshaft have been installed an additive containing E...

Page 105: ...inder to be serviced 3 Place piston for that cylinder at TDC to prevent valves from dropping into the cylinder 4 Compress valve spring with tool J 5892 and re move valve keys valve spring cap spring shield and valve spring 72881 b a a Valve Spring Compressor J 5892 b Rocker Arm Nut 5 Remove valve stem oil seal 72330 a a Valve Guide Seal 6 To install set valve spring close coiled end of spring is i...

Page 106: ... The head gasket may be holding cylinder head to block Use care when prying off cylinder heads DO NOT damage gasket surfaces DO NOT drop cylinder heads 3 Place cylinder head on wooden blocks to prevent damage to gasket surfaces Cleaning and Inspection 1 Clean gasket material and sealer from engine block and cylinder heads 2 Inspect sealing surfaces for deep nicks and scratches 3 Inspect for corros...

Page 107: ...tart engine set timing set idle speed and check for leaks Cylinder Head and Valve Conditioning Disassembly NOTE On LX models O ring seals are used only on intake valve stems 1 Using valve spring compressor compress valve spring J 8062 and remove valve locks Slowly release tool 2 Remove all valve components 3 Remove valves from cylinder head and place in a rack in order for reassembly in their orig...

Page 108: ...d if warped more than specified When head resurfacing is required cylinder head to intake manifold gasket surface on head must be milled to provide proper align ment between intake manifold and head 3 Inspect valves for burned heads cracked faces or damaged stems IMPORTANT Excessive valve stem to bore clear ance will cause excessive oil consumption and possible valve breakage Insufficient clearanc...

Page 109: ...eal Install new stud using Tool J 6880 as a guide Gauge should bottom on head Valve Guide Bore Repair IMPORTANT Be sure to measure valve stem di ameter of both the intake and exhaust valve as valve stem diameter may or may not be the same for both valves If 015 in oversize valve stems are required ream valve guide bores for oversize valves as follows 1 Measure valve stem diameter of old valve bein...

Page 110: ... be re placed When a valve head which is warped exces sively is refaced a knife edge will be ground on part or all of the valve head due to the amount of metal that must be removed to completely reface Knife edges lead to breakage burning or pre ignition due to heat localizing on this knife edge If the edge of the valve head is less than 1 32 in 0 8 mm after grind ing replace the valve Several dif...

Page 111: ...ooves of valve stem 72882 1 5 3 1 2 7 4 6 8 9 10 1 Valve Locks 2 Retainer 3 Rotator 4 Cap 5 Valve Guide Oil Seal 6 Valve Stem Oil Seal 7 Damper 8 Outer Spring 9 Intake Valve 10 Exhaust Valve 8 Check installed height of valve springs using a narrow thin scale Measure from spring seat to top of valve spring as shown If measurement ex ceeds specified height install a valve spring shim and recheck DO ...

Page 112: ...moval of engine from boat may be re quired 2 Drain crankcase oil 3 Remove starter motor 4 Remove oil pan screws oil pan and gasket s Installation 1 Clean sealing surfaces of engine block and oil pan 2 Apply a small amount of Quicksilver RTV Sealer to joints of rear seal retainer and joints of front cover IMPORTANT Quicksilver RTV Sealer sets up in about 15 minutes Be sure to complete assembly prom...

Page 113: ... pickup screen on pipe This is serviced as an assembly 4 If pickup screen and pipe assembly requires re placement mount pump in a soft jawed vise and extract pipe from pump Cleaning and Inspection 1 Wash all parts in cleaning solvent and dry with compressed air 2 Inspect pump body and cover for cracks or exces sive wear 3 Inspect pump gears for damage and excessive wear 4 Check for loose drive gea...

Page 114: ... to the hub and use of claw type puller may break the bond 4 Remove torsional damper with torsional damper remover and installer 72890 a a Torsional Damper Remover and Installer J 6978 E Installation IMPORTANT The inertia weight section of tor sional damper is assembled to the hub with a rub ber type material The installation procedure with proper tool must be followed or movement of the inertia w...

Page 115: ...il Seal Oil Seal Replacement Without Removing Front Cover REMOVAL 1 Remove torsional damper 2 Pry seal out of cover from the front with a large screwdriver being careful not to distort front cov er or damage crankshaft INSTALLATION IMPORTANT Correct rotation oil seal must be used to prevent oil leak 1 Apply Quicksilver Perfect Seal to seal retainer mating surface and apply grease to seal lips 2 In...

Page 116: ...nstaller Support cover around seal area with ap propriate tool as shown 74530 a a Crankcase Front Cover Seal Installer J 35468 2 Coat both sides of front cover gasket with Quick silver Perfect Seal and place in position on en gine 3 Install front cover making sure holes in cover align with dowel pins in block Torque front cover attaching screws to 100 lb in 11 N m 4 Install oil pan and torsional d...

Page 117: ...al indicator to engine block b Take readings around outer edge of flywheel Push in on flywheel to remove crankshaft end play c Maximum runout 008 in 0 203 mm 72353 a b a 008 in 0 203 mm Max Runout b Push Flywheel and Crankshaft Forward as Far as It Will Go when Taking Reading 4 Insert three rubber bumpers in Alpha coupler be fore installation on flywheel 72354 a a Rubber Bumper 5 Install drive cou...

Page 118: ...ain Seal Installer J 26817 A Cleaning and Inspection 1 Clean gasket material from mating surfaces 2 Inspect oil seal retainer for cracks or scored sur face 3 Inspect oil seal for worn dry or torn rubber Re place if necessary refer to Rear Main Oil Seal as outlined 4 Inspect alignment pin for damage replace if nec essary Installation 1 Coat seal lips with clean motor oil 2 Install gasket and oil se...

Page 119: ...available for service Inspection In general the lower half of the bearing except No 1 bearing shows a greater wear and the most dis tress from fatigue If upon inspection the lower half is suitable for use it can be assumed that the upper half is also satisfactory If the lower half shows evi dence of wear or damage both upper and lower halves should be replaced Never replace one half without replac...

Page 120: ... essary to regrind the crankshaft journal for use with the next undersize bearing 8 After selecting new bearing recheck clearance 9 Proceed to the next bearing After all bearings have been checked rotate the crankshaft to see that there is no excessive drag When checking No 1 main bearing loosen accessory drive belts so as to prevent tapered reading with plastic gauge Main Bearing Replacement 1 Re...

Page 121: ...earing is fitted to out of round crankpin br sure to fit maximum diameter of crankpin If bearing is fitted to minimum diameter and crankpin is out of round 001 0 025mm in terference between bearing and crankpin will re sult in rapid bearing failure a Place a piece of guaging plastic the full width of crankpin parallel to crankshaft b Install bearing connecting rod and cap c Place a piece of gaugin...

Page 122: ...rod caps as shown 006 014 0 152 0 356 72891 a a Take Measurement Here Connecting Rod Piston Assembly Removal 1 With oil pan oil pump and cylinder head removed use a ridge reamer to remove any ridge and or deposits from upper end of cylinder bore IMPORTANT Before ridge and or deposits are re moved turn crankshaft until piston is at bottom of stroke and place a cloth on top of piston to col lect cut...

Page 123: ...cations before pistons can be considered for re use 1 Clean varnish from piston skirts with a cleaning solvent DO NOT WIRE BRUSH ANY PART OF PISTON Clean ring grooves with a groove clean er and make sure oil ring holes are clean 2 Inspect piston for cracked ring lands skirts and pin bosses wavy worn ring lands scuffed or dam aged skirts and eroded areas at top of piston Re place pistons which are ...

Page 124: ...d Measure piston pin with a micrometer and piston pin bore with a dial bore gauge or inside micrometer If clearance is in excess of the 001 in 0 025 mm wear limit replace piston and piston pin assem bly Reassembly PISTONS AND PISTON PINS IMPORTANT When reassembling pistons and connecting rods the following must be kept in mind Piston and pin are machine fitted to each oth er and must remain togeth...

Page 125: ...elect rings comparable in size to cylinder bore and piston size 1 Slip compression ring in cylinder bore then press ring down into cylinder bore about 1 4 in 6 mm below ring travel Be sure that ring is square with cylinder wall 2 Measure gap between ends of ring with a feeler gauge as shown 72372 3 If gap between ends of ring is below specifica tions remove ring and try another for fit 4 Fit each ...

Page 126: ... outside of cylinder block Use piston ring compressor to compress rings Guide connecting rod into place on crankshaft journal with connecting rod bolt guide Use a hammer handle with light blows to install piston into bore Hold ring compressor firmly against cyl inder block until all piston rings have entered cyl inder bore IMPORTANT Be sure to install new pistons in same cylinders for which they w...

Page 127: ...eads 9 Remove main bearing caps and carefully lift crankshaft out of cylinder block 10 Remove crankshaft gear as shown 74476 11 If new main and or connecting rod bearings are to be installed remove main bearing inserts from cylinder block and bearing caps and or connect ing rod bearing inserts from connecting rod and caps Install new bearings following procedures outlined Cleaning and Inspection 1...

Page 128: ...nd torque nuts to 45 lb ft 61 N m 8 Turn crankshaft so mark on timing sprocket is fac ing camshaft 9 Install as outlined a Timing chain and sprocket on camshaft align marks with crankshaft b Timing chain cover c Oil pump d Dipstick tube and oil pan e Spark plugs f Torsional damper and crankshaft pulley g Water pump h Belts i Flywheel and drive coupler j Flywheel housing k Starter 10 Install new oi...

Page 129: ...all lobes are within speci fications remove dial indicator assembly 11 Install rocker arm and push rod Torque nuts to 20 lb ft 27 N m Removal 1 Remove valve lifters as previously outlined 2 Remove crankcase front cover as previously out lined 3 Remove fuel pump 4 Align timing gear marks then remove the two camshaft thrust plate screws by working thru holes in camshaft gear 5 Pull camshaft and gear...

Page 130: ...ar Replacement 1 If inspection indicates that camshaft gear or thrust plate should be replaced remove gear from camshaft 2 Place camshaft thru gear remover place end of remover on table of a press shaft out of gear CAUTION Position thrust plate so that woodruff key in shaft does not damage plate when shaft is pressed out of gear Also support hub of gear or gear will be seriously damaged 74477 b c ...

Page 131: ... with a dial indicator Camshaft gear run out should not exceed 004 in 0 1 mm and crankshaft gear run out should not exceed 003 in 0 07 mm 74440 Checking Timing Gear Run Out 4 If gear run out is excessive remove gear and clean burrs from shaft or gear must be replaced 5 Check backlash between timing gear teeth with a dial indicator Backlash should not be less than 004 in 0 010 mm or more than 006 i...

Page 132: ... will be necessary to posi tion pilot in rear camshaft bearing to remove rear intermediate bearing 5 Assemble driver on driver handle and remove front and rear camshaft bearings by driving to ward center of cylinder block Inspection Clean camshaft bearing bores in cylinder block with solvent and blow out with compressed air Be sure grooves and drilled oil passages are clean Installation CAUTION OI...

Page 133: ... be necessary to position pilot in rear camshaft bearing bore to install rear intermediate bear ing 2 Installing front and rear bearings a Install appropriate size remover and installer tool on drive handle b Index front bearing as explained in Impor tant above and drive it into position with tool Check position of oil hole s in bearing to ensure bearing is positioned correctly 74479 Removal And I...

Page 134: ...bores and main bearing webs CAUTION Measure cylinder walls for taper out of round or excessive ridge at top of ring travel This should be done with a dial indicator or inside micrometer Carefully work gauge up and down cylinder to de termine taper and turn it to different points around cylinder wall to determine out of round condition If cylinders exceed specifications bor ing and or honing will b...

Page 135: ...inders 4 When pistons are being fitted and honing is not necessary cylinder bores may be cleaned with a hot water and detergent wash After cleaning swab cylinder bores several times with light en gine oil and a clean cloth then wipe with a clean dry cloth CYLINDER BORING 1 Before using any type boring bar file off top of cyl inder block to remove dirt or burrs This is very im portant to prevent bo...

Page 136: ...uring honing operation PISTON SELECTION 1 Check used piston to cylinder bore clearance as follows a Measure cylinder bore diameter with a tele scope gauge 2 1 2 in 64 mm from top of cyl inder bore as follows 72386 b Measure piston diameter at skirt across cen ter line of piston pin as shown 72911 c Subtract piston diameter from cylinder bore diameter to determine piston to bore clear ance d Determ...

Page 137: ...4 A 72079 ELECTRICAL SYSTEMS STARTING SYSTEM ...

Page 138: ...A 11 Solenoid Switch 4A 12 Starter Motor Disassembly 4A 13 Cleaning and Inspection 4A 14 Page Armature Tests 4A 14 Field Coil Tests 4A 15 Loose Electrical Connections 4A 15 Turning the Commutator 4A 15 Reassembly 4A 16 Clearances 4A 17 Installation 4A 18 Delco PG200 and PG260 Starters 4A 18 Description 4A 18 PG200 Specifications 4A 19 PG260 Specifications 4A 19 Torque Specification 4A 19 Starting ...

Page 139: ...Starter Motor 50 812429A 50 812604A Important Information If the PG 200 or PG 260 starter has not been re moved it is recommended that it be removed and in spected as follows 1 Disconnect battery cables from battery 2 Disconnect wiring from starter Remove starter 3 Inspect starter motor drive housing replace if necessary 74517 a a Inspect This Area For Cracks STARTER BRACKET 74523 a a Starter Brac...

Page 140: ...ll ventilated and that bilge blower is in operation when charging DO NOT smoke or al low sources of spark or open flame in area when charging battery WARNING Do not use jumper cables and a booster battery to start engine Do not recharge a weak battery in the boat Remove battery and recharge in a venti lated area away from fuel vapors sparks or flames WARNING Battery electrolyte is a corrosive acid...

Page 141: ...fications 5 If readings are low recharge and retest 6 If readings remain low battery should be re placed Hydrometer Test WARNING Test battery in well ventilated area as gases given off by battery are hazardous 1 Hydrometer must be clean inside and out to in sure an accurate reading 2 Never take hydrometer readings immediately af ter water has been added 3 If hydrometer ha a thermometer draw liquid...

Page 142: ...HARGED 1 080 1 070 NOTE It is the activity of the acid hydrometer read ing which determines the activity of that cell Storage 1 Remove battery and clean exterior 2 Check fluid level and fill if low 3 Cover terminals and bolts with light coat of grease 4 Set battery on wood or in carton store in cool dry place 5 Check every 20 days for fluid level and slow charge IMPORTANT A discharged battery can ...

Page 143: ...s 10 Hours 6 1 2 Hours 5 Hours 4 Hours Initial rate for constant voltage taper rate charger To avoid damage charging rate must be reduced or temporarily halted if 1 Electrolyte temperature exceeds 125 F 52 C 2 Violent gassing or spewing of electrolyte occurs Battery is fully charged when over a two hour period at a low charging rate in amperes all cells are gassing freely and no change in specific...

Page 144: ... during the starting of the engine Because of this be sure to use correct type of slave solenoid for replacement Standard Type Slave Solenoid 74581 OFF OR RUN POSITION STARTING POSITION b c d e a b c a a From Key Switch 12 Volts In Start Position b To Ground c 12 Volts From Battery d 0 Volts From Starter e 12 Volts To Starter Switch Type Slave Solenoid 74582 OFF OR RUN POSITION STARTING POSITION b...

Page 145: ...YSTEM 4A 7 90 816462 2 695 Testing Replacement 1 Using continuity meter connect test leads as shown and connect 12 volt battery with jumper leads as shown 72630 2 If no meter movement is present replace sole noid ...

Page 146: ...1998317 10 6 70 120 5400 10 800 56 105 1588 2976 Pinion Clearance 010 140 0 25 3 5mm Bearing Depth Gear 011 014 0 28 0 38 Bearing Depth Drive Housing 009 017 0 25 0 45 Commutator End Frame Gap 025 MAX 0 6mm MAX Torque Specifications Fastener Location Lb Ft N m Starter Mounting Bolts 35 48 All Other Fasteners Tighten Securely Lubricants Sealants Description Part Number Quicksilver Liquid Neoprene 9...

Page 147: ...il Assembly 16 Leather Washer Commutator End Frame 17 Lower Commutator End Frame 6 7 21 25 29 30 31 27 28 26 18 Thru Bolt 19 Insulated Holder Field Frame Brush 20 Field Frame Brush Ground Holder 21 Field Frame Brush 22 Brush Lead Screw 23 Ground and Insulated Holders Support Package 24 Field Frame Brush Spring 25 Dowel Pin Field Frame 26 Shift Lever 27 Shift Lever Stud 28 Shift Lever Stud Washer 2...

Page 148: ... 816462 2 695 Starting System Components 72929 I B C A b d g h a c e f a Ignition Switch b Neutral Safety Switch c Starter Slave Solenoid d Circuit Breaker e Engine Ground Stud f Starter Solenoid g Wire Junction h 20 Amp Fuse ...

Page 149: ...etween large terminal RED PUR and other large terminal YEL RED causing starter motor to crank CAUTION The starter motor is designed to operate under great overload and produce a high horsepower for its size It can do this only for a short time since considerable heat accumulates and can cause serious damage For this reason the cranking motor must never be used for more than 30 seconds at any one t...

Page 150: ... tor strap terminal wire to remove terminal or wire will be too short 72632 a Solenoid Body b To Hold in Coil c Switch Terminal d Motor Connector Strap Terminal e To Pull in Coil f Contact Ring and Push Rod Assembly g Battery Terminal h Contact Finger i Screw j End Cover b c d e f g h i a J 4 Remove motor connector strap terminal and sol der new terminal in position 5 Remove and install new batter...

Page 151: ...end frame thru bolts end frame washer and field frame 72633 b c d a a Thru Bolts b End Frame c Washer d Field Frame 3 Remove screws center bearing plate and arma ture 72634 b c a a Screws b Bearing Plate c Armature 4 Slide thrust collar off armature shaft 5 Drive retainer ring toward armature 6 Remove snap ring retainer and clutch assembly ...

Page 152: ... their original length 5 16 in 8 mm or less 4 Check fit of armature shaft in bushing of drive housing Shaft should fit snugly Replace bush ing if worn Apply SAE 20 oil to bushing before reassembly Avoid excessive lubrication 5 Check fit of bushing in commutator end frame If bushing is damaged or worn excessively replace end frame assembly Apply SAE 20 oil to bushing before reassembly Avoid excessi...

Page 153: ... and leads do not contact field frame assembly during test or false reading will result 1 With continuity meter place one lead on field con nector bar and other lead on grounded brush 72636 2 If meter hand moves field coils are grounded and must be replaced Loose Electrical Connections If open soldered connection of armature to commuta tor leads is found during inspection resolder with res in flux...

Page 154: ...shaft away from pinion d Drive snap ring onto shaft and slide down into groove 72073 b a a Snap Ring b Groove e Assemble thrust collar on shaft with shoulder next to snap ring f Place thrust collar and retainer next to snap ring and using two pliers squeeze both until snap ring is forced into retainer 3 Place 4 or 5 drops of light engine oil in drive hous ing bushing Slide armature and clutch asse...

Page 155: ... 5 Measure distance between pinion and pinion re tainer 6 If clearance is not within limits of 010 140 in 0 25 3 5 mm it may indicate excessive wear of solenoid linkage shift lever yoke buttons or im proper assembly of shift lever mechanism Check for proper assembly and recheck gap If still ex cessive replace worn or defective parts since no provision is made for adjusting pinion clearance b c a 7...

Page 156: ...y Cable b Rubber Boot Delco PG200 and PG260 Starters Description The Delco PG 200 and PG260 starter motor features small permanent magnets mounted inside the field frame These magnets take the place of current car rying field coils mounted on iron pole pieces Internal gear reduction approximately 4 to 1 through plane tary gears results in armature speeds in the 7000 RPM range The armature and driv...

Page 157: ... Maximum PG260 Specifications Delco I D Engine No Load Test Brush Spring i Delco I D Number Engine Rotation Volts Min Amps Max Amp Min RPM Max RPM p g Tension Oz Grams 9000820 LH 10 6 60 95 2750 3250 83 104 oz 2352 2948 Pinion Clearance 101 160 025 4 06mm Bearing Depth Gear 011 014 0 28 038mm Maximum Bearing Depth Housing 009 017 0 4mm Maximum Torque Specification Fastener Location Lb Ft N m Start...

Page 158: ... 816462 2 695 Starting System Components 72929 I B C A b d g h a c e f a Ignition Switch b Neutral Safety Switch c Starter Slave Solenoid d Circuit Breaker e Engine Ground Stud f Starter Solenoid g Wire Junction h 20 Amp Fuse ...

Page 159: ...ent Magnets 2 End Frame 3 Ball Bearing 4 Brushes with Holder 5 Brush Spring 6 Armature 7 Shield 8 Gear 9 Roller Bearing 10 Planetary Gear and Shaft Assembly 11 Drive 12 Collar 13 Retaining Ring 14 Thrust Collar 15 Drive Housing 16 Roller Bearing 17 Nut 18 Screw 19 Thru Bolt Contains Starter Solenoid Plunger Return Spring and Shift Lever ...

Page 160: ...mature 5 Field Frame with Permanent Magnets 6 Washer 7 Shield 8 Planetary Gears 9 Shaft 10 Gear 11 Drive 12 Collar 13 Retaining Ring 14 Thrust Collar 15 Drive Housing 16 Nut 17 Solenoid 18 Solenoid Drive Arm 19 Screw 3 20 Thru Bolt 2 21 Rubber Grommet 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 17 18 19 20 21 16 ...

Page 161: ...trance of moisture and dirt However periodic inspection is re quired as follows 1 Inspect terminals for corrosion and loose connec tions 2 Inspect wiring for frayed and worn insulation 3 Check starter mounting bolts for tightness Starter Motor Repair Removal WARNING Disconnect battery cables at battery before re moving starter 1 Disconnect battery cables from battery 2 Disconnect wires from soleno...

Page 162: ...rmature b Field Frame 4 Pull end frame off bearing 72063 b a a End Frame b Bearing 5 Remove shield 72065 a a Shield 6 Use a screwdriver as shown to disengage shift lever from drive 72064 a a Shift Lever 7 Remove thrust collar retaining ring and collar Remove drive 72067 b c d a a Thrust Collar b Retaining Ring c Collar d Drive ...

Page 163: ... and hold brushes against commutator Check brushes for wear refer to Brushes and Brush Holder 3 Inspect armature commutator If badly grooved or out of round turn down and undercut commuta tor 4 Inspect all roller bearing surfaces for wear Check that bearings roll freely If any roughness is felt replace bearings 5 Inspect planetary gear assembly Gears must mesh easily and roll freely with no bindin...

Page 164: ...ush holder must be installed on armature before installing armature bearing Using the correct size driver press on inner bearing race until it contacts shoulder of armature shaft Gear Bearing REMOVAL Using the correct size driver press bearing out of gear INSTALLATION 1 Using the correct size driver press bearing into gear from direction shown to depth specified 72625 Installation Direction a a De...

Page 165: ...rrect size driver press bearing out of housing 72626 b a a Drive End Housing b Bearing INSTALLATION 1 Using the correct size driver press bearing into housing from direction shown to depth specified 72626 INSTALLATION DIRECTION a a Depth 009 017 in 0 25 0 45 mm 2 Lubricate bearing with a small amount of Quicksil ver 2 4 C Marine Lubricant with Teflon Brushes and Brush Holder INSPECTION Replace bru...

Page 166: ...down against commutator as shown 72069 b c a a Brush Holder b Commutator c Brush 3 Install armature bearing as previously described PG200 Reassembly 1 Install end frame on brush holder Align holes of end frame with holes of brush holder Tighten screws securely 72063 b a b a Holes of End Frame b Holes of Brush Holder 2 Insert armature into field frame Align brush hold er lead with notch in field fr...

Page 167: ...th cupped surface facing end of shaft away from pinion d Position snap ring on upper end of shaft and hold in place with block of wood Strike wood block with hammer thus forcing snap ring over end of shaft Slide snap ring down into groove 72073 b a c a Snap Ring b Groove c Retainer e Assemble thrust collar on shaft with shoulder next to snap ring f Position retainer and thrust collar next to snap ...

Page 168: ... inserting armature into planetary gears 72061 b c a a Shield b Brush Lead c Solenoid Terminal 9 Install thru bolts and brush lead Tighten fasten ers securely IMPORTANT Do not overtighten thru bolts Over tightening will bend end frame 72060 b a a Thru Bolts b Brush Lead Standard Starter Slave Solenoid Testing Replacement 1 Using continuity meter connect test leads as shown and connect 12 volt batt...

Page 169: ...ver mechanism Replace worn or defective parts since no provision is made for ad justing pinion clearance 72077 b c a a Pinion b Retainer c Feeler Gauge Installation IMPORTANT Install special mounting shim if equipped between starter motor and engine block 1 Place starter motor in position and install mount ing bolts Torque bolts to 30 lb ft 41 N m 2 Connect YELLOW RED wire to terminal S of so leno...

Page 170: ...4 B 71855 ELECTRICAL SYSTEMS IGNITION SYSTEM ...

Page 171: ...igital Distributorless Ignition System 4B 11 Specifications 4B 11 Torque Specifications 4B 11 Tools Lubricants Sealants 4B 11 Spark Plugs 4B 11 Overspeed Prevention Control 4B 11 Description 4B 12 DDIS System Components 4B 12 Spark Advance Control 4B 13 Advance Curve Chart Reference Only 4B 13 MCM 3 0 L DDIS Models 4B 13 Spark Advance Control 4B 14 Advance Curve Chart Reference Only 4B 14 MCM 3 0 ...

Page 172: ...Warning WARNING Electrical ignition and fuel system components on your MerCruiser are designed and manufac tured to comply with U S Coast Guard Rules and Regulations to minimize risks of fire and explo sion Use of replacement electrical ignition or fuel sys tem components which do not comply with these rules and regulations could result in a fire or ex plosion hazard and should be avoided ...

Page 173: ...ng Jumper 91 818812A1 Kent Moore Tools Description Part Number Module Tester J24642 Specifications Coil Description Specification Coil Part Number 392 7803A4 Max Operating Amps 1 1 Primary Resistance 1 1 1 5 Ohms Secondary Resistance 9 400 11 700 Ohms Secondary Continuity 67 77 Resistor Wire 1 8 2 Ohms Distributor Model 3 0L Condenser 18 25 mfd Point Dwell 39 45 Point Gap 016 in 0 5mm Point Spring...

Page 174: ...well 39 45 Point Spring Tension 20 27 oz 567 765 g IMPORTANT Distributor advance curve charts do not include the initial engine timing Basic initial timing must be added to chart for total advance curve IMPORTANT The spark advance is controlled by the ignition module 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5 10 15 20 25 30 35 ENGINE R P M TOTAL SPARK ADVANCE MINUS INITIAL TIMING 70808 3 M...

Page 175: ...t spark plugs are not in terchangeable with non tapered with gasket spark plugs 4 Clean spark plug seating area DO NOT use gas kets on taper seat plugs Install spark plugs and torque to 15 lb ft 20 N m Heat transfer and a gas tight seal must be achieved Spark Plug Wires 1 Inspect spark plug wires for damage 2 Check spark plug wires for continuity 3 Replace any wires that are cracked cut or have da...

Page 176: ...ss nor dress point satisfactorily Do not attempt to remove all roughness nor dress point surfaces down smooth Merely remove scale or dirt 3 Badly burned or pitted contact points should be replaced and cause of trouble determined and corrected BURNED POINTS 1 Contact point burning results from high voltage presence of oil or other foreign material defective condenser and improper point adjustment 2...

Page 177: ... Contact point pressure must fall within specified limits Step 8 preceding Weak tension will cause chatter which results in arcing and burning of points and an ignition miss at high speed while excessive tension will cause undue wear of contact points cam and rub bing block Contact point pressure should be checked with a spring gauge Scale should be hooked to breaker lever and pull exerted at 90 t...

Page 178: ...gine with starter adjust dwell with a screwdriver to obtain reading on dwell me ter as specified in Specifications and tighten lock screw Dwell reading will be unsteady using this method IMPORTANT Cam angle increases as point open ing is decreased and vice versa 50654 Cam Angle a Cam b Direction or Rotation c Breaker Points d Dwell In Degrees When Points Are Closed e Points Open 5 Install rotor an...

Page 179: ...ce resistor wire if reading is not within specifications 4 Reconnect wires to coil and choke 5 Breaker Point Ignition Models For instructions on replacing resistor wire refer to Section 4 Part E Distributor Repair Removal 1 Disconnect distributor primary lead from coil ter minal 2 Remove distributor cap and rotor IMPORTANT If necessary to remove leads from distributor cap mark position on cap towe...

Page 180: ... side play al lowed is 002 in 0 05 mm 5 Remove shaft from housing and check shaft for being bent with a dial indicator and V blocks Maximum runout is 002 in 0 5 mm 6 Remove weight cover check weights and weight stop for wear Check weights for free movement on pins 74551 a b d b c a Weight Cover b Weight Springs c Weights d Weight Stop Studs Advance Weights and Components Reassembly 1 Replace centr...

Page 181: ...continuing to crank slowly until pointer lines up with timing mark on crankshaft pulley 2 Position distributor to opening in block in normal installed attitude 3 Position rotor to point toward front of engine with distributor housing held in installed attitude then turn rotor counterclockwise approximately 1 8 turn more to the left and push distributor down to engage camshaft It may be necessary t...

Page 182: ... side of 0 Top Dead Center 72328 b a a Degree Marks b Timing Mark 5 Adjust timing by loosening distributor clamp and rotating distributor body as required until timing mark on damper or pulley lines up with the mark on tab specified in Specifications Tighten clamp and recheck location of timing mark 6 Stop engine and remove timing light ...

Page 183: ...plifier 65 7 3 Ignition coils 20 2 2 Spark Plugs 14 mm 15 20 Tools Lubricants Sealants Mercury Marine Special Tools Description Part Number Dwell Meter 91 59339 Magneto Analyzer 91 76032 Remote Starter Switch 91 52024A1 Timing Light 91 99379 Volt Ohm Meter 91 99750 Timing Jumper 91 818812A1 Spark Plugs Spark Plug Gap 035 In 0 9 mm 3 0L DDIS AC MR43T NGK BR6FS Champion RV15YC4 3 0LX DDIS AC MR43LTS...

Page 184: ...ge towers The coils are fired on both com pression stroke and exhaust stroke DDIS System Components MCM 3 0L 3 0LX Models 50402 IGNITION COIL MOTOR SENSOR IGNITION AMPLIFIER IMPORTANT Models equipped with Digital Distri butorless Ignition System D D I S have an over speed prevention control built into the system The control module limits engine speed to 5000 RPM when speed exceeds 5000 RPM the con...

Page 185: ...18811T1 Module Advance 18 Initial Timing 8 BTDC Total Advance 26 Advance Curve Chart Reference Only IMPORTANT Advance curve charts do not in clude the initial engine timing Basic initial timing must be added to chart for total advance curve EXAMPLE Advance curve chart shows 13 spark ad vance at 2000 RPM Add 8 BTDC initial timing for a total spark advance of 21 at 2000 RPM MCM 3 0 L DDIS MODELS 500...

Page 186: ...18811T2 Module Advance 18 Initial Timing 8 BTDC Total Advance 26 Advance Curve Chart Reference Only IMPORTANT Advance curve charts do not in clude the initial engine timing Basic initial timing must be added to chart for total advance curve EXAMPLE Advance curve chart shows 8 spark ad vance at 2000 RPM Add 8 BTDC initial timing for a total spark advance of 16 at 2000 RPM MCM 3 0 LX DDIS MODELS 500...

Page 187: ...on sys tem parts while engine is running Do not reverse battery cable connections System is negative ground Do not disconnect battery cables while en gine is running Ignition Amplifier 1 Disconnect ignition amplifier form coil With the ignition switch in the RUN position check volt age at terminal from ignition amplifier Reading should be battery voltage a a Check Voltage Here 2 Disconnect engine ...

Page 188: ... 5 Ohms 1 a to c 1 9 2 5 Ohms 1 At Room Temperature 68 F 20 C 1 Ohmmeter set on the Rx1 Scale 2 Secondary coil resistance a Disconnect spark plug wires from coil high voltage towers b Measure resistance between towers as shown 74672 3 4 2 1 At Room Temperature 68 F 20 C 1 Ohmmeter set on the Rx1000 Scale HIGH VOLTAGE TOWERS RESISTANCE RANGE 1 to 4 11 3 15 5 Ohms 1 2 to 3 11 3 15 5 Ohms 1 3 Coil in...

Page 189: ...ition discon nect motion sensor from ignition amplifier Mea sure resistance between sensor terminals Resis tance range 140 to 180 ohms Rx10 If resistance is not within specifications replace motion sensor IMPORTANT Motion sensor must be at room tem perature 68 F 20 C when testing a a Check Resistance Between These Two Points Shift Interrupter Switch 1 Disconnect ignition amplifier from engine har ...

Page 190: ...strokes To install the motion sensor number one piston does not have to be TDC of its compression stroke Simply align the timing mark on zero 1 Crank engine until timing mark is on zero 2 Align hole not roll pin hole in gear with notch on motion sensor housing Install new gasket Apply Quicksilver 2 4 C Marine Lubricant with Teflon to gear 74390 b a a Hole b Notch in Motion Sensor Housing NOTE When...

Page 191: ...r housing 2 Start engine and run at normal idle speed under 900 RPM use tachometer in boat instrumenta tion 3 Adjust timing by loosening clamp and rotating motion sensor as required until timing mark on pulley aligns with 8 BTDC mark on tab Torque clamp bolt to 20 lb ft 27 N m and recheck loca tion of timing mark 4 Stop engine and disconnect timing light IMPORTANT GM engine timing marks on tab are...

Page 192: ...At Idle RPM EST Ignition 1 BTDC Timing must be set using a special procedure as outlined in this section Timing cannot be properly set using the conven tional method Spark Plugs Spark Plug Gap 035 In 0 9 mm 3 0L AC MR43T NGK BR6FS Champion RV15YC4 3 0LX AC MR43LTS NGK BPR6EFS Champion RS12YC GM 4 Cylinder In line Firing 50683 Firing Order 1 3 4 2 Description EST or Electronic Spark Timing is a Hig...

Page 193: ...mber of pole piece teeth four for a four cylinder engine The electronic mod ule is small enough to allow it to be mounted inside the distributor and contains the circuits necessary for dwell control and advance of the timing Molded into the module is a two prong connector for the coil terminals and four prong connector Only three of the four terminals of the second connector are used by MerCruiser...

Page 194: ...ite If not replace coil 3 Set ohmmeter to Rx100 scale and connect to 12 volt terminal b and terminal c Reading should be approximately 4 ohms If not replace coil 4 Set ohmmeter to Rx1 scale and connect to 12 volt terminal b and tachometer terminal f Reading should be approximately 4 ohms If not replace coil 5 Set ohmmeter to Rx100 high scale Connect ohmmeter to 12 volt terminal b and to coil high ...

Page 195: ... Module Advance See Notice Initial Timing 1 BTDC Total Advance 23 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5 10 15 20 25 30 35 ENGINE R P M TOTAL SPARK ADVANCE 70808 15 MAX MIN NOTICE Advance curve includes initial timing DO NOT add initial timing degrees to total advance degrees ...

Page 196: ...emporarily join the engine harness wires together IMPORTANT Do not fail to reconnect these two wires to the shift interrupt switch when timing procedures are complete 4 With timing light connected check timing Timing should be 1 BTDC 5 If required loosen distributor hold down clamp and rotate distributor to obtain specified timing 6 Secure distributor hold down clamp and recheck timing as above 7 ...

Page 197: ...ELECTRICAL SYSTEMS CHARGING SYSTEM 4 C 72078 ...

Page 198: ...cifications 4C 19 Tools Sealants 4C 19 Torque Specifications 4C 20 Description 4C 20 Precautions 4C 20 Page Exploded View 4C 21 System Components 4C 22 Periodic Maintenance 4C 22 Drive Belt Tension Adjustment 4C 23 Alternator 4C 23 Troubleshooting Tests Alternator on Engine 4C 23 Circuitry Test 4C 23 Alternator Output Test 4C 23 Harness Voltage Test 4C 24 Open Diode Trio Test 4C 24 Current Output ...

Page 199: ...inimize risks of fire and explo sion Use of replacement electrical ignition or fuel sys tem components which do not comply with these rules and regulations could result in a fire or ex plosion hazard and should be avoided Mando 55 Amp Alternator Specifications Description Specification Excitation Circuit 1 3 2 5 Volts Current Output 50 Amp Minimum Voltage Output 13 9 14 7 Volts Condenser Capacity ...

Page 200: ...e rotor field winding and the rotor is turned the movement of the magnetic fields created induces an alternating current into the stator windings The rectifier bridge then changes this alternating current to direct current which appears at the output terminal A diode trio also is connected to the stator windings to supply current to the regulator and the rotor field during operation Voltage output...

Page 201: ...tor lead from alternator regulator terminal when the alternator is being driven by the engine 5 ALWAYS remove negative battery cable from battery before working on alternator system 6 When installing battery BE SURE to connect the positive battery cable to the positive bat tery terminal and the negative grounded bat tery cable to negative battery terminal 7 If a charger or booster battery is to be...

Page 202: ...ension and adjust if necessary as ex plained under Drive Belt Tension Adjustment 4 Check alternator mounting bolts for adequate tightness 5 Inspect slip ring end frame flame arrestor screen for debris and clean if necessary using com pressed air or a cloth Screen MUST BE clean or alternator may overheat 72078 a a Inspect This Area Drive Belt Tension Adjustment Alternator 1 Install drive belt on pu...

Page 203: ...ned under Drive Belt Tension Adjustment Circuitry Test Perform the following tests using a 0 20 volt DC volt meter to check that all of the circuits between the al ternator and the other components within the alterna tor system are in good condition OUTPUT CIRCUIT 1 Connect positive voltmeter lead to alternator output terminal and negative lead to a ground terminal on alternator 2 Wiggle engine wi...

Page 204: ...3 Voltmeter should indicate battery voltage If bat tery voltage is not present check sensing circuit RED PURPLE lead for loose or dirty connection or damaged wiring 72786 b c d a e a Output Wire ORANGE b Excitation Wire PURPLE c Sensing Wire RED PURPLE d Voltmeter 0 20 Volts e Ground Current Output Test Perform this test to check if alternator is capable of producing rated current output using a 0...

Page 205: ... test If necessary charge battery with a battery charger or allow engine to run a sufficient length of time to fully charge bat tery before taking reading 1 Connect positive voltmeter lead to positive RED battery terminal and negative voltmeter lead to negative BLACK terminal 2 Start engine and run at fast idle until engine reaches normal operating temperature Adjust engine speed to 1500 2000 RPM ...

Page 206: ... 14 5 volts inspect brushes and slip rings for wear dirt or damage If brushes and slip rings are good alter nator is faulty internally Disassemble alternator and test components as outlined under Alterna tor Repair following 72971 b c d a a Ground b Brush Regulator Assembly c Brush Terminal d Jumper Wire Solder Connection to Ground Alternator Repair Removal 1 Disconnect negative battery cable from...

Page 207: ...4 Sensing Wire RED PURPLE 5 Excitation Wire PURPLE 6 Cover 7 Tie Strap 8 Rubber Gasket 9 Condenser 10 Insulator 3 11 Bolt 4 12 End Frame Rear 13 Cap 2 14 Brush Regulator Assembly 15 Rectifier Assembly 16 Flat Washer 17 Screw 18 Stator 19 Rotor and Slip Rings 20 Retaining Plate 21 Front Bearing 22 End Frame Front 23 Screw 3 24 Fan Spacer 25 Fan 26 Pulley Spacer 27 Pulley 28 Lockwasher 29 Nut ...

Page 208: ...rew and two regulator leads Then pull regulator cover away from rear end frame 72963 b c d a a Regulator Leads b Nuts 4 c Phillips Head Screw d Regulator Cover 3 Remove stud cover insulator two nuts and tie strap from brush regulator assembly 4 Remove two brush regulator attaching screws and remove brush regulator assembly 72823 a Screws b Brush Regulator Assembly c Stud Cover Insulator d Tie Stra...

Page 209: ... downward Be sure that bench is clean and free of metal chips Remove nuts washers insulators and condenser from output and ground studs 9 Turn end frame over stator upward and remove one Phillips head screw which secures rectifiers to end frame 72826 a Rectifier Assembly b Phillips Head Screw b a 10 Separate stator and rectifier assembly from rear end frame using screwdriver slots 11 Unsolder the ...

Page 210: ...te b a 14 Remove front bearing from front end frame using an arbor press and a suitable size mandrel Dis card bearing 72830 b a c a Press b Mandrel c Bearing 15 If rotor slip rings or rear bearing requires replace ment entire rotor must be replaced Parts cannot be purchased separately Cleaning and Inspection 1 Clean all parts with a clean soft cloth DO NOT use solvent or electrical components may ...

Page 211: ...d for wear Inspect drive surface of pulley sheaves for trueness excessive wear grooves pits nicks and corrosion Repair damaged sur faces if possible with a fine file and a wire brush or replace pulley if beyond repair Drive surfaces MUST BE perfectly true and smooth or drive belt wear will be greatly accelerated Component Testing ROTOR 1 Test rotor field circuit for opens shorts or high re sistanc...

Page 212: ...be shorting or grounding out due to centrifugal force Replace rotor if all other electri cal components test good STATOR IMPORTANT Stator leads MUST BE discon nected from rectifier for this test 1 Test stator for grounds Test 1 using an ohmme ter set on R x1 scale as follows a Connect one lead of ohmmeter to one of the stator leads and the other lead to stator frame Be sure that lead makes good co...

Page 213: ... 1 through 3 for two other rectifiers in heat sink 5 Replace assembly if any of the rectifiers is shorted or open 72147 a Heat Sink b Rectifier Terminal c Test These Two Rectifiers in Same Manner b a c Positive Rectifier and Diodes CAUTION DO NOT use a test instrument with more than a 12 volt source in the following test as rectifier may be damaged 1 Connect one lead of an ohmmeter set on R x1 sca...

Page 214: ...Capacity Test must be 5 mfd b Condenser Short or Leakage Test c Condenser Series Resistance Test 2 Replace condenser if test results are not within specifications Reassembly 1 Install new front bearing into front end frame bear ing bore using an arbor press If necessary use a bearing driver that contacts outer race only 72835 a b a Press b Mandrel 2 Install front bearing retaining plate using thre...

Page 215: ...sition stator down with rear end frame up and reinstall insulators nuts and condenser a Insulators 3 b Nuts 5 ONE REMOVED c Condenser 72561 c a b b 8 Position rear end frame and stator assembly over front end frame and rotor assembly and align scribe marks on each scribed during disassem bly Hand press end frames together then install four screws Tighten screws securely 72561 a Rear End Frame b St...

Page 216: ...brushes against slip rings 72837 a Brush Regulator Assembly b Mounting Screws a b 11 Install tie strap to rectifier stud and stud on brush rectifier assembly Tighten nuts securely 72823 a Studs b Tie Strap b a 12 Install cover with one Phillips head screw and two nuts Install two leads with nuts 72963 a Phillips Head Screw b Nuts 4 c Leads b c a 13 Install insulator caps 72078 a Insulator Caps a ...

Page 217: ...lternator Replacement Parts Warning WARNING Electrical ignition and fuel system components on your MerCruiser are designed and manufac tured to comply with U S Coast Guard Rules and Regulations to minimize risks of fire and explo sion Use of replacement electrical ignition or fuel sys tem components which do not comply with these rules and regulations could result in a fire or ex plosion hazard an...

Page 218: ...ttery and regulates the field current to maintain alternator voltage within pre scribed limits for properly charging the battery Cur rent output of the alternator does not require regula tion as maximum current output is self limited by the design of the alternator As long as the voltage is reg ulated within the prescribed limits the alternator can not produce excessive current A cut out relay in ...

Page 219: ...ear End Frame 15 Star Washers 2 16 Insulator 17 Insulating Washers 2 4 3 1 2 5 8 9 4 5 9 8 7 10 5 6 11 12 15 13 22 24 14 16 17 18 19 23 20 21 25 26 29 30 31 32 33 34 27 28 BLACK RED PURPLE GREEN BROWN 4 18 Nut 19 Washer 20 Insulating Washer 21 Insulator 22 Negative Rectifier 23 Positive Rectifier Diode Trio 24 Stator 25 Rotor and Slip Rings 26 Snap Ring 27 Bearing 28 Front End Frame 29 Fan Bushing...

Page 220: ...ter areas CAUTION Remove all battery cables from battery before conducting the following check to prevent acci dentally shorting out electrical system 1 Inspect entire alternator system for corroded or loose connectors 2 Check wiring for frayed or worn insulation 3 Check alternator drive belt for excessive wear cracks fraying and glazed surfaces Also check drive belt tension and adjust if necessar...

Page 221: ...s of time 2 Check physical condition and state of charge of battery as outlined in Battery Storage in Sec tion 4A Battery MUST BE at least 75 1 230 specific gravity of fully charged to obtain valid re sults in the following tests If not charge battery before testing system 3 Inspect entire alternator system wiring for de fects Check all connections for tightness and cleanliness particularly batter...

Page 222: ...3082 a Excitation Wire PURPLE b Sensing Wire RED PURPLE c Voltmeter 0 20 Volts d Ground c d a b OPEN DIODE TRIO TEST 1 With ignition on and engine not running check for battery voltage at alternator output terminal Test 1 and 1 5 to 3 0 volts at regulator terminal Test 2 73083 a Regulator Terminal b Output Terminal c Ground d Voltmeter 0 20 Volts c d a b 2 Connect a jumper wire between regulator a...

Page 223: ... tower and ground it to block Turn on all accessories and crank engine over with starter motor for 15 20 se conds 5 Turn off accessories and reinstall coil hi tension lead Start engine and adjust engine speed to 1500 2000 RPM Quickly observe ammeter Reading should be at least 30 amps 6 If reading is low stop engine and connect a jump er wire between alternator output terminal and regulator termina...

Page 224: ...l Test 2 73083 a Regulator Terminal b Output Terminal c Ground d Voltmeter 0 20 Volts c d a b 3 Remove the four screws which secure the regula tor to the alternator 4 Connect a jumper wire between field terminal GREEN WIRE and ground If 1 5 to 3 0 volts are present at regulator terminal regulator is defec tive If voltage is not present at regulator terminal there is an open field circuit brushes s...

Page 225: ...rom alternator 3 Remove alternator belt 4 Remove alternator Disassembly 1 Using an oversized V belt to protect the pulley clamp alternator in vise as shown Remove pulley nut and lockwasher 72828 a 7 8 In Wrench b Oversized V Belt to Protect Pulley b a 2 Remove pulley fan woodruff key and spacer 73087 a Nut b Lockwasher c Pulley d Woodruff Key e Fan f Spacer g Alternator b c d a e f g 3 Disconnect ...

Page 226: ...ether CAUTION Do not insert screwdriver blades deeper than 1 16 in 1 58 mm to avoid damaging stator windings 8 Using a suitable holding fixture separate front end frame and stator assembly from rear end frame using two thin blade screwdrivers posi tioned 180 degrees apart from each other at the locations shown 73091 a Front End Frame b Stator c Rear End Frame d Scribe Marks b a c d 9 While support...

Page 227: ...iscoloration as this is usually a sign of a shorted or grounded winding or a shorted diode f Regulator Inspect leads for damaged insu lation g Front and Rear Housings Inspect for cracks distortion stripped threads or wear in bearing bore from bearing outer race spin ning in bore Replace if defective h Fan Inspect for cracked or bent fins broken welds or worn mounting hole from fan spin ning on sha...

Page 228: ...ress push against cap screw to remove slip rings 4 Install a universal puller plate under bearing 5 Using an arbor press remove bearing Installation 1 Press new rear bearing all the way onto rotor shaft until inner race contacts shoulder with an arbor press and a bearing driver that contacts inner bearing race only as shown Use extreme care to prevent damage to field winding leads IMPORTANT Be sur...

Page 229: ... no continuity meter should not move c If continuity does exist rotor field circuit is grounded Inspect slip ring terminals to be sure that they are not bent and touching rotor shaft Also be sure that excess solder is not grounding terminals to rotor shaft If cause for ground cannot be found unsolder field wind ing leads from slip ring terminals and connect ohmmeter between one of the leads and ro...

Page 230: ...nd complete rotor as sembly must be replaced b c d a a Field Winding Leads b Slip Rings c Rotor Shaft d Pole Pieces 73112 Stator IMPORTANT Stator leads MUST BE discon nected from rectifiers and diode trio for this test CAUTION Excessive heat from de soldering may cause damage to rectifiers or diode trio assembly when disconnecting leads 1 Test stator for grounds using an ohmmeter set on Rx1 scale ...

Page 231: ...ed to their original positions 2 Using an ohmmeter set on Rx1 scale check for continuity between rectifier terminal and heat sink Reverse ohmmeter leads and recheck Con tinuity should be observed in one direction polar ity only 3 Check other two rectifiers in same manner 4 Replace assembly if any of the rectifiers is shorted or open 73102 POSITIVE RECTIFIER AND DIODE TRIO CAUTION Do not use a test...

Page 232: ... diodes in same manner 7 Replace diode trio if any of the diodes is shorted or open 73104 Condenser 1 Using Magneto Analyzer 91 76032 and accom panying instructions perform the following con denser tests a Condenser Capacity Test must be 5 mfd b Condenser Short or Leakage Test c Condenser Series Resistance Test 2 Replace condenser if test results are not within specifications Reassembly 1 Solder p...

Page 233: ...es together then install four screws Torque screws to 50 60 lb in 5 6 6 7 N m 73105 b c a d a Front End Frame b Stator c Rear End Frame d Scribe Marks 4 Install brush holder into rear end frame and slide forward to depress brushes against slip ring In sert two screws and tighten securely 73090 a Attaching Screws b Brush Holder a b 5 Attach field lead to brush assembly Install regula tor and felt g...

Page 234: ...n f Spacer g Alternator b c d a e f g 8 Using an oversized belt to protect the pulley clamp alternator in vise as shown Tighten pulley nut to 35 50 lb ft 48 68 N m 73108 a Oversized Belt b Pulley b a Installation 1 Install alternator on engine 2 Install alternator belt and adjust as outlined under Drive Belt Tension Adjustment 3 Tighten mounting bolts to specifications 4 Reconnect wiring harness t...

Page 235: ...ng battery Mercury Marine does not manufacture any battery isolator systems Battery isolators must be bought from an outside manufacturer Mercury Marine sug gests following the manufacturer s instructions care fully IMPORTANT Alternators used on MerCruiser en gines ARE NOT equipped with an isolation diode CAUTION Follow battery isolator manufacturer s instruc tions for wire gauge Battery isolator ...

Page 236: ...62 2 695 Battery Isolator Diagram 72934 Alternator with Voltmeter Circuit Typical Wiring Shown NOTE 1 Disconnect ORANGE Wire From Alternator BATT Terminal Splice Sufficient Guage Wire To The ORANGE Wire And Connect As Shown NOTE 1 ...

Page 237: ...4 D 72747 ELECTRICAL SYSTEMS INSTRUMENTATION ...

Page 238: ...t 4D 4 Tachometer 4D 4 Testing 4D 4 Gauge Replacement 4D 4 Senders 4D 5 Page Oil Pressure 4D 5 Testing 4D 5 Dual Station Sender Identification 4D 5 Water Temperature Sender 4D 5 Testing 4D 5 Installation 4D 6 Dual Station Sender identification 4D 7 Fuel Tank Sender 4D 7 Flange Type 4D 7 Testing 4D 7 Capsule Type 4D 8 Testing 4D 8 Switches 4D 8 Ignition Key Switch 4D 8 Testing 4D 8 Audio Warning Sy...

Page 239: ...ES These gauges may be wired so that the illumination lighting is provided from the ignition switch or a sepa rate instrumentation lighting switch By removing contact strip I from between terminal and the screw as shown following and supplying a separate 12 V power supply to the screw connec tion illumination lights can be operated independent of ignition switch 72966 b c a a 12 V Power Supply fro...

Page 240: ...lighting effects colored sleeves are available through the Quicksilver Accessories and can be assembled to the bulb 72968 a a 12 V Power Supply from Ignition Switch Ignition Switch Lighting Circuit Position 72969 b a a 12 V Power Supply from Ignition Switch b 12 V Power Supply from Separate Instrumentation Lighting Circuit Separate Instrumentation Lighting Circuit Posi tion Gauges Oil Fuel and Tem...

Page 241: ...e of gauge being tested must read at position B If not replace gauge 72749 Position B Typical Battery Gauge TESTING 1 Remove cables from battery and fully charge bat tery 2 Connect negative jumper lead from battery to gauge terminal G GND 3 Connect positive jumper lead from battery to gauge terminal I or 12 V 72750 Typical 4 Check gauge reading if not as shown replace gauge 72751 Typical ...

Page 242: ... testing speedometer gauge for accuracy the air supply used for the test must be regulated to the specified air pressure Do not apply excessive air pressure to speedometer gauge 1 Apply air pressure directly to speedometer gauge specified in chart and note gauge reading Light tapping of pressure gauge is required during ac curacy check 2 If gauge readings are not within specifications gauge is def...

Page 243: ...Remove wire from sender terminal 2 Connect ohmmeter between sender terminal and sender case Check ohms reading without engine running zero pressure then check reading with engine running Compare oil pressure and ohms readings as shown in following chart 72754 b c d a a Positive Lead b Negative Lead c Wire Removed d Oil Pressure Sender Oil Pressure PSI Ohms Reading PSI Single Dual 0 227 257 113 5 1...

Page 244: ...itable container such as metal to hold the water Avoid use of glass containers unless the operator first confirms for himself herself that the glass container is an appropri ate high temperature vessel Because the components will reach high tem peratures DO NOT handle materials or com ponents until COMPLETELY cooled 2 Follow these instructions a With ohmmeter connected as outlined and using suitab...

Page 245: ...1 Disconnect wire from terminal on sending unit and ground wire from sending unit mounting screw 2 Remove sending unit from fuel tank 3 Connect ohmmeter between sending unit termi nal and sending unit housing 4 With float arm in FULL position arm horizontal ohmmeter should read 30 ohms 5 ohms 72755 b a a Ohmmeter Leads b Vertical Float Arm 5 With float arm in EMPTY position arm vertical meter shou...

Page 246: ...til fuel capsule indicator reads FULL Ohmmeter should read 30 ohms 5 ohms Fuel capsule is defective if not within specifica tions 72759 a a Capsule Reading Full Switches Ignition Key Switch TESTING WARNING Disconnect battery cables from battery before testing ignition key switch with wires still con nected to switch 1 Before testing key switch check all fuses and or circuit breakers in electrical ...

Page 247: ... of electricity Failure to follow appropriate procedures can cause burns or shock which can result in severe personal injury or death TESTING 1 Turn key to RUN position engine off 2 Wait 7 to 14 seconds for horn to sound 3 If horn does not sound a Connect jumper wires as shown b If horn does not sound replace it 4 If horn worked in Step 3 a Connect jumper wires as shown b Repeat Step 2 c If horn s...

Page 248: ...e protection preferably full face shield or safety glasses The appropriate heat source should only be electric Heat source should be operated by a qualified person Be sure to follow all instruc tions of the manufacturer of the heat source The heat source should be checked each time it is used to be sure it is functioning properly The thermometer used in the test should be a high temperature thermo...

Page 249: ...r to chart below for specifications 48952 Switch Opens 150 170 F 60 77 C Closes 190 200 F 88 93 C 87 86080 Switch Opens 175 195 F 79 91 C Closes 215 225 F 102 107 C 72767 b a a 48952 Switch with Red Mylar Sleeve b 87 86080 Switch with Black Mylar Sleeve Switch Identification 4 Turn heat source off Allow sand to cool Note thermometer reading to ensure switch opens up at specified temperature 5 Repl...

Page 250: ...4 E 72938 ELECTRICAL SYSTEMS WIRING DIAGRAMS ...

Page 251: ...t Ignition Dual Station Using A Neutral Safety Switch In Only One Remote Control 4E 7 EST and DDIS ignition Dual Station Using A Neutral Safety Switch In Only One Remote Control 4E 8 Page Breaker Point Ignition Dual Station Using A Neutral Safety Switch In Both Remote Controls 4E 9 EST and DDIS Ignition Dual Station Using A Neutral Safety Switch In Both Remote Controls 4E 10 Battery Meter Gauge 4E...

Page 252: ...TAN Water Temperature Sender to Gauge LIGHT BLUE LIT BLU Oil Pressure Sender to Gauge PINK PNK Fuel Gauge Sender to Gauge BROWN WHITE BRN WHT Trim Sender to Trim Gauge PURPLE WHITE PUR WHT Trim Trailer Switch RED RED Unprotected Wires from Battery RED PURPLE RED PUR Protected Fused Wires from Battery RED PURPLE RED PUR Protected 12V to Trim Panel ORANGE ORN Alternator Output PURPLE YELLOW PUR YEL ...

Page 253: ... SHIFT INTERRUPT SWITCH ALTERNATOR OPTIONAL AUDIO WARNING WATER TEMPERATURE HEAT SWITCH WATER TEMPERATURE SENDER OPTIONAL OIL PRESSURE SWITCH TERMINAL BLOCK ENGINE GROUND GROUND STUD ON ENGINE FLYWHEEL HOUSING GROUND SCREW ON INNER TRANSOM PLATE CIRCUIT BREAKER STARTER SLAVE SOLENOID TRIM SENDER OIL PRESSURE SENDER ...

Page 254: ...RE SENDER ALTERNATOR CHOKE SHIFT INTERRUPT SWITCH TERMINAL BLOCK ENGINE GROUND GROUND STUD ON ENGINE FLYWHEEL HOUSING GROUND SCREW ON INNER TRANSOM PLATE CIRCUIT BREAKER OIL PRESSURE SENDER OPTIONAL OIL PRESSURE SWITCH STARTER SLAVE SOLENOID TRIM SENDER OPTIONAL AUDIO WARNING WATER TEMPERATURE HEAT SWITCH ...

Page 255: ...ST Ignition NEW STYLE BOTTLE OLD STYLE BOTTLE NOTE 1 Audio Warning System Standard On 3 0LX Models NOTE 2 Gray lead for use with service tachometer A Ignition Components B Starting Charging and Choke Components C Audio Warning System Components D Instrumentation Components ...

Page 256: ...ed to instrument terminal that has an 8 gauge BLACK ground har ness wire connected to it NOTE 3 Audio warning is standard 3 0LX models and optional on 3 0L CAUTION Audio warning buzzer is not external ignition proof therefore DO NOT mount buzzer in engine or fuel tank compartments 50585 TACHOMETER OIL PRESSURE WATER TEMPERATURE BATTERY METER AUDIO WARING BUZZER OPTIONAL TRIM INDICATOR IGNITION SWI...

Page 257: ...ccessory panel may be taken from this connection Load must not exceed 40 amps Panel ground wire must be connected to instrument terminal that has an 8 gauge BLACK ground harness wire connected to it NOTE 3 Audio warning is standard 3 0LX models and optional on 3 0L Ignition Switch Tachometer Oil Pressure Water Temperature Battery Meter To Engine Harness NOTE 3 Trim Indicator NOTE 1 NOTE 1 NOTE 2 7...

Page 258: ...PUR PURPLE RED RED TAN TAN WHT WHITE YEL YELLOW LIT LIGHT DRK DARK NOTE 1 BROWN WHITE wire is taped back at instrument end If installing on boat that is equipped with MerCruiser Stern Drive BROWN WHITE wire is connected to the trim sender terminal block Also can be used for an accessory limit 5 amps NOTE 2 An accessory fuse panel may be connected at this location The combined current draw of the p...

Page 259: ...ITCH ON ENGINE ROCKER ARM COVER NOTE 1 BROWN WHITE wire is taped back at instrument end If installing on boat that is equipped with MerCruiser Stern Drive BROWN WHITE wire is connected to the trim sender terminal block Also can be used for an accessory limit 5 amps NOTE 2 An accessory fuse panel may be connected at this location The combined current draw of the primary station and secondary statio...

Page 260: ...ENSION HARNESS TO ENGINE NOTE 4 NOTE 4 NOTE 1 NOTE 1 BROWN WHITE wire is taped back at instrument end If installing on boat that is equipped with MerCruiser Stern Drive BROWN WHITE wire is connected to the trim sender terminal block Also can be used for an accessory limit 5 amps NOTE 2 An accessory fuse panel may be connected at this location The combined current draw of the primary station and se...

Page 261: ...e is taped back at instrument end If installing on boat that is equipped with MerCruis er Stern Drive BROWN WHITE wire is connected to the trim sender terminal block Also can be used for an accessory limit 5 amps NOTE 2 An accessory fuse panel may be connected at this location The combined current draw of the primary station and secondary station MUST NOT exceed 5 amps NOTE 3 Tape back and insulat...

Page 262: ...his Terminal to Ground Terminal on Water Temperature or Oil Pressure Gauge Cruiselog 72815 b a a Connect to Ignition Switch Activated 12 Volt Positive Source PURPLE Wire b Connect to Negative Ground BLACK Wire Fuel Gauge and Sender 72816 BLACK PINK BLACK PINK PINK WHITE PURPLE BLACK NOTE A Connect to I Ignition Terminal or Accessory Ter minal of ignition switch NOTE B Connect to NEGATIVE Battery T...

Page 263: ...er Temperature Gauge 72819 b c a BIA Color Code Leads to a BLACK a Ground b PURPLE b Switched 12 _Volt Terminal c TAN c Sender Lead Oil Pressure Gauge 72819 b c a BIA Color Code Leads to a BLACK a Ground b PURPLE b Switched 12 Volt Terminal c LIGHT BLUE c Sender Lead Clock 72818 b c a a a Connect to a Terminal on an Adjacent Gauge or to Another Suitable Ground b Connect to Instrument Harness RED P...

Page 264: ...5 A FUEL SYSTEM FUEL PUMP ...

Page 265: ...tions 5A 2 Fuel Delivery System 5A 2 Recommendations 5A 2 Description 5A 2 Page Fuel System Components Typical 5A 3 Water Separating Fuel Filter 5A 3 Replacement 5A 3 Fuel Pump Fuel Filter 5A 4 Replacement 5A 4 Testing Fuel Pump 5A 4 Fuel Pump Replacement 5A 5 Removal 5A 5 NOTICE For information and procedures on troubleshoot ing refer to SECTION 1C 5A FUEL DELIVERY SYSTEM 90 816462 2 695 ...

Page 266: ...NOT USE TEFLON TAPE Thread brass fitting or plug into fuel filter base until finger tight Tighten fitting or plug an additional 1 3 4 to 2 1 4 turns using a wrench DO NOT OVER TIGHTEN Install fuel line To prevent over tightening hold brass fitting with suitable wrench and tighten fuel line connectors securely Check for fuel leaks Torque Specifications Description Lb Ft N m Fuel Inlet and Outlet Fi...

Page 267: ... System Recommendations WARNING Boating industry standards BIA ABYC etc fed eral standards and Coast Guard regulations MUST BE adhered to when installing fuel delivery system When designing and installing fuel delivery system the following information MUST BE observed 1 Fuel tank should be mounted below carburetor level if possible If tank is mounted above carbu retor level gravity feed may cause ...

Page 268: ...Ring Filter should be replaced when fuel flow is restricted or filter flow is questionable DO NOT attempt to flush out filter Replacement NOTICE Refer to Precautions in this section BE FORE proceeding 1 Disconnect battery cables from battery 2 Remove fuel filter from base A filter wrench may be needed to loosen element 3 Lubricate sealing ring s of new filter with SAE en gine oil 4 Install new fil...

Page 269: ...mp 5 Install new filter 6 Tighten retaining screw securely 7 Install safety wire and tighten securely 8 Start and run engine 9 Check for gasoline leaks 10 If leaks exist STOP ENGINE and recheck con nections Testing Fuel Pump NOTICE Refer to Precautions in this section BE FORE proceeding 1 Disconnect battery cables from battery 2 Remove fuel line from carburetor or outlet side of fuel pump 3 Instal...

Page 270: ...rass fittings or plugs into fuel filter base can crack casting and or cause a fuel leak Apply 592 Loctite Pipe Sealant with Teflon to threads of brass fitting or plug DO NOT USE TEFLON TAPE Thread brass fitting or plug into fuel filter base until finger tight Tighten fitting or plug an additional 1 3 4 to 2 1 4 turns using a wrench DO NOT OVER TIGHTEN Install fuel line To prevent over tightening h...

Page 271: ...5 B 72681 FUEL SYSTEM MERCARB 2 BARREL CARBURETOR ...

Page 272: ...4 Precautions 5B 5 Fuel Supply Connections 5B 5 Maintenance 5B 5 Flame Arrestor with Carburetor Cover 5B 5 Page Fuel Inlet Filter 5B 6 Choke Inspection 5B 7 Adjustments 5B 7 Pump Rod 5B 7 Choke Setting 5B 8 Choke Unloader 5B 8 Preliminary Idle Speed and Mixture 5B 9 Final Idle Speed and Mixture 5B 9 Repair 5B 10 Removal 5B 10 Installation 5B 10 Exploded View Parts List 5B 13 Cleaning and Inspectio...

Page 273: ...NING Electrical ignition and fuel system components on your MerCruiser are designed and manufac tured to comply with U S Coast Guard Rules and Regulations to minimize risks of fire and explo sion Use of replacement electrical ignition or fuel sys tem components which do not comply with these rules and regulations could result in a fire or ex plosion hazard and should be avoided Torque Specificatio...

Page 274: ... 3 8 10 Spring Loaded Needle 9 16 14 See Note Float Drop 1 3 32 27 See Note Pump Rod 1 5 32 29 Choke Setting Two Marks To The Lean Side Choke Unloader 5 64 080 2 Idle Mixture Screws 1 1 4 Turns Float Weight 9 Grams Maximum Primary Jet Size 1 45mm 1 60mm 1 60mm 1 65mm Power Valve Size 0 74mm 0 74mm 0 74mm 0 84mm Venturi Cluster I D Number 442 592 464 593 Accelerator Pump Discharge Hole Size 025 0 6...

Page 275: ...buretor Part Number 500 Ft 1525 m and Below 5000 9000 Ft 1525 2745 m 9000 2745 m and Above 3 0L 1389 9562 3310 806077 1 45 mm Stock Jets 1 40 mm 1 35 mm 3 0L 3 0LX 1389 815396 3310 806078 3310 805924 1 60 mm 1 50 mm 1 45 mm 3 0LX 1389 815397 1 65 mm 1 55 mm 1 50 mm JET SIZES Jet Size Quicksilver Part Number 1 30 3302 811849 1 35 3302 811850 1 40 3302 811851 1 45 3302 9050 1 50 3302 811852 1 55 330...

Page 276: ...y 0 5 cc less fuel and the hole farthest away will give about 1 0 cc less fuel 73131 c a b a Full Accelerator Pump Stroke b 0 5 cc Less Fuel per Stroke c 1 0 cc Less Fuel per Stroke The technician should be able to correct most bog ging problems with this 3 holed lever providing the bogging is caused by the carburetor When instal ling the 3 holed lever remove any metal ball that someone may have p...

Page 277: ...e and high ly explosive under certain conditions Be sure that ignition key is OFF DO NOT smoke or allow sources of spark or flame in the area while chang ing fuel filter Wipe up any spilled fuel immediate ly WARNING Make sure no fuel leaks exist before closing en gine hatch Fuel Supply Connections CAUTION DO NOT operate engine without cooling water be ing supplied to water pickup holes in gear hou...

Page 278: ...n Hose f Flame Arrestor Fuel Inlet Filter NOTICE Refer to Precautions in this section BE FORE proceeding 1 Remove in the following order a Fuel line from fuel inlet filter nut b Fuel inlet filter nut and small gasket c Large gasket d Filter e Spring f Small gasket from inside filter nut 72406 b c d a e f a Fuel Line b Fuel Inlet Filter Nut c Gasket Large d Gasket Small e Filter f Spring 2 Clean fi...

Page 279: ...r choke cleaner Fol low directions on can IMPORTANT Choke valve and shaft and lever as sembly is not serviceable If valve and or shaft and lever assembly is worn or damaged air horn assembly must be replaced Adjustments NOTICE Refer to Precautions in this section BE FORE proceeding Pump Rod 1 Back out idle speed screw until it no longer con tacts idle cam 72284 b a a Idle Speed Screw b Idle Cam 2 ...

Page 280: ...rews and adjust as shown 2 Tighten three choke cover retaining screws se curely Choke Unloader 1 Hold throttle valves completely open 2 Gently press down on choke plate 3 Using a 080 5 64 in drill rod or or appropriate gauge slide rod between upper edge of choke plate and air horn assembly Rod should just slide through 72684 b c a a 080 In 0 2 mm Drill Rod b Choke Plate c Air Horn 4 Bend tang on t...

Page 281: ... under Specifications with boat in the water engine at normal operating temperature and drive unit in forward gear To adjust idle speed and mixture proceed as follows IMPORTANT DO NOT attempt to compensate for other engine problems incorrect ignition timing faulty ignition components low compression vacuum leaks etc with carburetor adjustments This will only cover the problem which must be correct...

Page 282: ...r from en gine without draining fuel from bowl Contents of fuel bowl may then be inspected for contamina tion as carburetor is disassembled 1 Remove ventilation hose from flame arrestor then remove flame arrestor IMPORTANT Place a clean cloth in bores of car buretor to prevent dirt and foreign material from falling into bores 2 Turn fuel supply off at fuel tank 3 Disconnect throttle cable from car...

Page 283: ...speed and idle mixture as outlined un der Adjustments as previously outlined The following is a step by step procedure for com pletely overhauling carburetor removed from engine In many cases however complete overhaul is not necessary and in these cases only the steps re quired to repair the carburetor malfunction should be performed Read the instructions carefully to prevent doing any unnecessary...

Page 284: ...2 BBL CARBURETOR 90 816462 2 695 72686 1 2 3 4 5 6 7 8 9 10 11 12 14 15 16 17 18 19 21 22 23 24 25 26 29 30 31 32 27 28 35 36 37 38 39 40 41 42 43 44 45 46 47 48 51 52 53 54 55 49 50 56 57 58 59 61 62 60 13 34 20 33 ...

Page 285: ...ting Needle 28 Spring 29 Washer 30 Nut 31 Clip Pump Rod 32 Washer Locking 33 Nut 34 Throttle Lever 35 Spring 36 Screw Idle Speed Adjustment 37 Throttle Body 38 Screw 39 Washer 40 Gasket 41 Check Ball 42 Spring 43 Retainer 44 Screw 45 Lever Assembly 46 Screw 47 Choke Housing 48 Gasket 49 Air Horn 50 Inlet Needle And Seat 51 Pin 52 Screw 53 Gasket 54 Screw 55 Screw 56 Flat Washer 57 Lock Washer 58 G...

Page 286: ...283 b c a a Accelerator Pump Rod b Retainer Clip c Pump Shaft and Lever Assembly 3 Remove idle cam screw Also remove choke rod by pivoting rod as required until retaining ear on rod and slot in choke lever align allowing rod to be pulled out 72282 b c a a Idle Cam Screw b Idle Cam c Choke Rod 72286 b c a a Choke Rod b Choke Lever c Slot 4 Remove air horn attaching screws as shown 72280 a a a a a A...

Page 287: ...rn Assembly b Float Bowl Assembly 6 Invert air horn and carefully lay on bench 7 Remove float hinge pin and lift float assembly from air horn 72288 b a a Float Hinge Pin b Float Assembly 8 Check float weight as shown 72122 b a a Grams Scale b Float 9 Remove air horn gasket and baffle 72399 b a a Baffle b Air Horn Gasket ...

Page 288: ...3302 9029 b Solid Type Needle Kit 3302 9407 Needle and Seat Assemblies 12 Loosen accelerator pump screw Slide pump shaft and lever assembly and washer out of air horn then remove accelerator pump assembly 72398 b c a a Setscrew b Lever Assembly c Pump Assembly 13 Remove retainer clip and washer from pump shaft and lever assembly then remove accelera tor pump assembly 72409 b c a a Pump Assembly b ...

Page 289: ... 3 Remove main metering jets 72291 b a b a Main Metering Jets b Gaskets Not Shown IMPORTANT Use care when removing venturi cluster to prevent damaging brass tubes which protrude from bottom of cluster DO NOT RE MOVE TUBES These tubes are permanently pressed into the venturi cluster and are not re placeable 4 Remove three venturi cluster screws and care fully lift cluster and venturi gasket straigh...

Page 290: ...tle body assembly attaching screws and lockwashers and remove throttle body and gasket from float bowl 72294 b c d a b a Screws b Lockwashers Not Shown c Throttle Body d Gasket Not Shown 2 Remove idle mixture adjusting needle and spring 72293 b a a Idle Mixture Adjusting Needle b Spring 3 Remove idle speed adjustment screw and spring if replacement is necessary 72395 b a a Idle Speed Screw b Sprin...

Page 291: ... seat is worn or damaged replace with new needle and seat assembly IMPORTANT Float needle and seat are factory matched and tested and should be replaced as a set only b Float Assembly and Hinge Pin Check float density to see if it is saturated with fuel by comparing weight of float with specifications If weight is high float assembly must be re placed Check hinge pin and holes for wear c Fuel and ...

Page 292: ...2293 b a a Idle Mixture Adjusting Needle b Spring 2 Thread idle speed adjustment screw and spring into throttle lever 72395 b a a Idle Speed Screw b Spring 3 Turn float bowl assembly upside down and place new throttle body gasket on bowl making sure gasket is properly positioned on location dowels 72295 b a b a Throttle Body Gasket b Locating Dowels 4 Install throttle body assembly on float bowl a...

Page 293: ...ner firmly into slots 72408 a b c a Check Ball b Spring c Retainer 2 Install new gasket on venturi cluster as shown 72296 b a a Venturi Cluster I D No 421 b Gasket 3 Install venturi cluster in carburetor as shown 72397 b a a Venturi Cluster b Gasket 4 Install flat washer and new fiber washer on center screw Lockwashers and flat washers are used on outer screws Tighten screws evenly and secure ly 7...

Page 294: ...et Not Shown 7 Place accelerator pump spring in pump well 72402 a a Accelerator Pump Spring AIR HORN ASSEMBLY IMPORTANT Accelerator pump assembly MUST BE installed correctly If pump assembly is installed incorrectly top of pump assembly will contact air horn casting 1 If accelerator pump assembly was removed from pump lever secure pump assembly to pump lever with washer and retainer clip as shown ...

Page 295: ...aft is hitting lever Tighten setscrew securely 72398 b c a a Setscrew b Lever Assembly c Pump Assembly 3 Install needle seat and gasket Tighten securely 72289 b c a a Needle Seat b Gasket c Screwdriver IMPORTANT Float needle and needle seat are factory matched and tested and should be re placed as a set only 4 Place needle assembly in needle seat 72287 b a a Needle Assembly b Needle Seat 5 Install...

Page 296: ...sure float level using Universal Carburetor Gauge 91 36392 Measure from gasket to toe of float 72298 a a Measure from This Point to Gasket 72687 a a Measurement With 2 Piece Solid Inlet Needle 3 8 in 10 mm Measurement With Spring Loaded Inlet Needle 9 16 in 14 mm 3 Bend float arm up or down at point shown to ob tain specified dimension 72688 a a Bend Float Arm at This Point 4 Visually check float ...

Page 297: ...loat bowl making sure accelerator pump is correctly positioned in fuel well Lower air horn straight down to install 72400 a b a Air Horn Assembly b Float Bowl Assembly 6 Install seven short and one long air horn attaching screws Tighten screws evenly and securely 72280 a a a a a Air Horn Attaching Screws 7 Place end of choke rod in choke lever and collar assembly 72299 b a a Choke Rod b Choke Leve...

Page 298: ...at cam is free to move without binding 72282 b c a a Screw b Idle Cam c Choke Rod 10 Place accelerator pump rod end with ear in hole in pump shaft and lever assembly 72393 b a a Accelerator Pump Rod b Pump Shaft and Lever Assembly 11 Insert remaining end of accelerator pump rod into hole in throttle lever and secure with retainer clip 72283 b c a a Accelerator Pump Rod b Throttle Lever c Retainer ...

Page 299: ...y Install choke lever tighten screw se curely 72401 b c a a Choke Housing b Choke Housing Attaching Screws c Choke Lever 2 Install choke cover Make sure hook on end of choke coil engages with choke lever Rotate choke cover until index marks align as shown Tighten screws securely 72403 b c a a Scribed Mark b More Choke c Less Choke ...

Page 300: ...6 A 50628 COOLING SYSTEM SEAWATER COOLED MODELS ...

Page 301: ...p Pump 6A 2 Thermostat 6A 2 Removal 6A 2 Testing 6A 2 Installation 6A 3 Cold Weather Or Extended Storage 6A 4 Auxiliary Hot Water Heater Installation 6A 5 Cooling System Flow Diagram 6A 7 NOTICE For information and procedures on troubleshoot ing refer to SECTION 1C NOTICE For cold weather or extended storage information and procedures refer to SECTION 1B 6A SEAWATER COOLED MODELS 90 816462 2 695 ...

Page 302: ... F 62 C Flush Cooling System If engine is operated in salty polluted or mineral laden waters cooling system should be flushed periodically preferably after each use to reduce corrosion and prevent the accumulation of deposits in the system Cooling system also should be thoroughly flushed prior to storage WARNING When flushing cooling system with boat out of water be certain that area in vicinity o...

Page 303: ...AL for about 10 minutes or un til discharge water is clear Watch temperature gauge on instrument panel to ensure that engine does not overheat 5 Stop engine turn off water tap and remove flush device Thermostat Removal 1 Drain water from cylinder block and exhaust man ifold 2 Disconnect Hose from thermostat cover 3 Remove thermostat cover attaching bolts and lock washers then remove and screws 4 R...

Page 304: ...accu rate results d Plug in tester and observe temperature at which thermostat opens thermostat drops off thread Thermostat must open at specified temperature stamped on thermostat e Continue heat water until a temperature 25 F 14 C above temperature specified on ther mostat valve must be completely open at this temperature f Replace a thermostat that fails to meet all of the preceding tests Insta...

Page 305: ... be opened or the water inlet hose reconnected prior to starting the engine IMPORTANT Observe the following information to ensure complete draining of cooling system Engine must be as level as possible A wire should be repeatedly inserted into all drain holes to ensure there are no obstruc tions in passages IMPORTANT To prevent threads in manifolds el bows and cylinder blocks from rusting out duri...

Page 306: ...30 lb ft 41 N m 7 Remove water hose from exhaust manifold and fill manifold with coolant Install hose and tighten clamp securely Auxiliary Hot Water Heater Installation When connecting a cabin heater or hot water heater to a MerCruiser engine certain requirements must be met Supply hose from engine to heater and re turn hose from heater to engine MUST NOT EXCEED 5 8 in 15 8 mm I D inside diame ter...

Page 307: ...hown below Cut approximately 3 4 in 19 mm out of hose to maintain proper hose configuration 73572 a a Cut Hose at This Location 4 Install return fitting in hose and tighten hose clamps securely 73572 a a Return Fitting 5 Connect hot water return hose to return fitting and tighten hose clamps securely 6 Ensure that hoses do not rub or chafe against any engine components ...

Page 308: ...an opening on the front of the cylinder block On some models sea water may be pumped through an oil cooler before going to the circulating pump The centrifugal pump then circulates the seawater through the block head and manifolds removing heat given off by these parts as it passes through After passing through the en gine the seawater is pumped into the exhaust elbow where it mixes with exhaust g...

Page 309: ...6 B 73665 COOLING SYSTEM CLOSED COOLING MODELS ...

Page 310: ... Testing 6B 6 Installation 6B 7 Changing Coolant 6B 7 Closed Cooling Section 6B 8 Coolant Recommendations 6B 8 Change Intervals 6B 8 Draining Instructions 6B 8 Draining Diagram 6B 9 Cleaning System 6B 10 Closed Cooling Section 6B 10 Seawater Section 6B 10 Flushing Seawater Section of Closed Cooling System 6B 11 Draining Seawater Section of Closed Cooling System 6B 12 Recommissioning 6B 13 Filling ...

Page 311: ...a vacuum leak usually at the hose leaving the reser voir or the gasket under the recovery filler cap The gasket seals against the outer rim of the filler neck IMPORTANT The coolant antifreeze flows around the outside of the cooling tubes while seawater flows through the inside of the cooling tubes in the heat exchanger Engine exhaust manifold is seawater cooled Stern drive seawater pickup pumps se...

Page 312: ...turn to allow any pressure to escape slowly then push down and turn cap all the way off 1 Remove pressure cap from heat exchanger 2 Wash cap with clean water to remove any depos its or debris from sealing surfaces 3 Inspect rubber seal on cap for cuts cracks or oth er signs of deterioration If seal is damaged cap MUST BE replaced 4 Inspect coolant recovery gasket for deterioration and replace if b...

Page 313: ...ure in system and is causing coolant to boil over 3 Clean inside of filler neck to remove any deposits or debris Examine lower inside sealing surface for nicks or other damage Surface must be per fectly smooth to achieve a good seal between it and rubber seal on cap Also check locking cams on sides of filler neck to be sure that they are not bent or damaged If locking cams are bent or damaged pres...

Page 314: ... coolant recovery bottle Use a 2 3 ft 61 91 cm long hose for this test 2 Route this hose so a U is formed 3 Put enough coolant into hose to fill the center 4 or 5 inches 10 13 cm of the U 4 Observe the U while the engine is running a During Idle and Warm Up Some coolant and or air will leave the reservoir b During Cruising Speed 2500 3500 RPM Coolant and or air leaving the reservoir should stop af...

Page 315: ...with clean water to remove any depos its or debris from sealing surfaces 3 Inspect gasket if used and rubber seal on cap for tears cuts cracks or other signs of deterioration Replace gasket if damaged or entire cap if rub ber seal is damaged 72714 b c a a Rubber Seal Cap MUST BE Replaced if Damaged b Gasket Look for Cracks under Gasket c Locking Tabs 1 Hidden 4 Check that locking tabs on cap are n...

Page 316: ...p and water to remove any deposits or debris 2 Inspect thermostat for corrosion or other visible damage 3 If thermostat is suspected of producing insuffi cient engine temperature check thermostat for leakage by holding it up to lighted background Light leakage around the thermostat valve indi cates that thermostat is not closing completely and should be replaced A small amount of leak age at one o...

Page 317: ...ater to cool to a tem perature 10 F 5 C below specified tempera ture on thermostat Thermostat must be com pletely closed at this temperature f Replace a thermostat that fails to meet all of the preceding tests Installation 1 Remove thermostat housing and gaskets Dis card gaskets 2 Clean gasket surfaces on thermostat cover ther mostat housing and intake manifold 3 Position lower gasket with continu...

Page 318: ...ly then push down and turn cap all the way off IMPORTANT A wire should be inserted into drain holes to ensure that foreign material is not ob structing the drain holes On later models with two piece petcock removal of petcock may be re quired so that wire can be inserted completely into drain hole IMPORTANT Engine must be as level as possible to ensure complete draining of cooling system IMPORTANT...

Page 319: ...OOLED MODELS 6B 9 90 816462 2 695 Draining Diagram 73665 a b a b b b a Remove and Lower Hoses To Drain b Remove Drain Plugs Repeatedly Clean Out Holes Using A Stiff Piece Of Wire Until Entire System Is Drained ...

Page 320: ...lt silt lime etc collect on the inside of the tubes thus reducing heat transfer and greatly decreasing heat exchanger efficiency It is therefore recommended that the seawater section of the heat exchanger be cleaned at least once every two years or whenever decreased cooling efficiency is suspected as follows IMPORTANT It may be necessary to remove heat exchanger on some models If heat exchanger i...

Page 321: ...nto boat CAUTION To prevent engine or stern drive unit damage DO NOT run engine or drive unit without water being supplied to water intake openings on gear hous ing CAUTION Watch temperature gauge at dash to ensure the engine does not overheat 1 Connect flushing attachment as follows NOTE If flushing cooling system with boat in water raise drive unit to trailer position install flushing at tachmen...

Page 322: ...ighten hose clamps securely Draining Seawater Section of Closed Cooling System NOTICE For cold weather or extended storage information and procedures refer to SECTION 1B NOTE It may be necessary to lift bend or lower hoses to allow water to drain completely when hoses are disconnected CAUTION If boat is in the water or is to remain in the water seacock if so equipped must remain closed un til engi...

Page 323: ...e clamps securely If NOT equipped with seacock seawater inlet hose must remain disconnected and plugged until en gine is to be restarted 9 Insert a small wire repeatedly to make sure that vent holes and water drain holes and passages as shown are unobstructed and open 71216 70134 b c d e f a c f a Speedometer Pitot Tube b Trim Tab Cavity Vent Hole c Trim Tab Cavity Drain Passage d Gear Housing Wat...

Page 324: ...e and subsequent overheating damage to stern drive unit DO NOT operate engine without water being supplied to seawater pickup pump CAUTION Models with belt drive seawater pickup pump must be in the water when running engine be cause garden hose will not supply enough water to system at higher RPM 3 With pressure cap off start engine and run at fast idle 1500 1800 RPM Add coolant solution to heat e...

Page 325: ...C 6 EXHAUST SYSTEM MANIFOLD ...

Page 326: ... Requirements 6C 1 Engines With Thru Drive Unit Exhaust 6C 1 Removal 6C 1 Cleaning And Inspection 6C 2 Installation 6C 2 Upper Exhaust Pipe And Shutter Replacement 6C 3 Lower Exhaust Pipe Replacement 6C 4 NOTICE For information and procedures on troubleshoot ing refer to SECTION 1C 6C MANIFOLD 90 816462 2 695 ...

Page 327: ...caused by water in the en gine will not be covered by MerCruiser Warranty unless this damage is the result of defective part s Determine if exhaust elbow risers are required by tak ing measurements A and B as shown with boat at rest in the water and maximum load aboard Subtract B from A If A minus B is less than specified in chart select appropriate size exhaust elbow riser kit and exhaust extensi...

Page 328: ... If plugs are removed coat threads with Perfect Seal before reinstalling IMPORTANT If manifold to cylinder head studs have broken install all new studs with Loctite 8831 AFTER checking head and manifold sur faces for warpage Also use all new manifold at taching nuts 5 Check for cracks 6 To test manifold body for leaks block off plates plugs or short hoses with plugged ends must be used One block o...

Page 329: ...cable to carburetor Adjust as outlined in Removal Installation and Alignment 6 Connect fuel line and electric choke wires 7 Reinstall exhaust and cooling hoses 8 Reconnect battery cables to battery Tighten se curely 9 Start engine check for exhaust water and fuel leaks and adjust carburetor idle speed and mix ture Upper Exhaust Pipe and Shutter Replacement IMPORTANT Engine does not have to be re m...

Page 330: ...Remove to Change Shutter b Clamps 2 c Grommet 2 d Shutter Opens Downward Lower Exhaust Pipe Replacement 1 Remove stern drive unit 2 Remove engine then upper exhaust pipe 3 Remove screws and lockwashers that secure lower exhaust pipe to gimbal housing 50634 b a a Exhaust Pipe b Screws 4 2 Under Exhaust Pipe 4 Remove exhaust pipe and O ring 5 Clean mating surfaces on pipe and gimbal hous ing 6 Place...

Page 331: ...7 A 71317 POWER STEERING PUMP ...

Page 332: ...ing System 7A 2 Pump Drive Belt Tension Adjustment 7A 2 Pump Pulley Replacement 7A 3 Removal 7A 3 installation 7A 3 Page Power Steering Pump And Cooler 7A 4 Replacment 7A 4 Installation 7A 7 Low Pressure Hose Control Valve to Cooler 7A 8 Removal 7A 8 Installation 7A 8 Priority Valve Kit 79691A1 Information 7A 10 Installing Reservoir 7A 10 Installing Priority Valve 7A 11 Filling System with Fluid 7...

Page 333: ...ate engine without cooling water be ing supplied to water pickup pump or water pump impeller will be damaged and subsequent over heating damage to engine may result WARNING Always disconnect battery cables from battery before working on engine to prevent fire or explo sion CAUTION Do not pry on power steering pump or alternator when adjusting belt tension Serious damage may result Checking Power S...

Page 334: ...p to correect level IMPORTANT Use only Quicksilver Power Trim and Steering Fluid or automatic transmission fluid ATF Dexron II in power steering system 2 Turn steering whell back and forth to end of travel i each direction several times then recheck fluid level and add fluid if necessary 3 Install vented fill cap CAUTION DO NOT operate engine without water being sup plied to seawater pump pickup o...

Page 335: ...l has an end on it that will not mushroom the end of the pump shaft DO NOT use Kent Moore Tool J 21239 to remove these pulleys This tool has a tapered end and will damage the shaft 3 Install Kent Moore Tool J 25034 on end of pulley and shaft as shown 4 While holding tool with suitable wrench turn threaded screw until pulley is removed 72821 a a Kent Moore Pulley Removal Tool J 25034 INSTALLATION I...

Page 336: ... in this sec tion BEFORE proceding 1 Install pulley 74562 2 Install boltsand torque to 20 lb ft 27 N m 74563 a a Bolts and Lockwashers 3 Install 40 inch 1016 mm drive belt 74564 a a 40 inch 1016 mm Drive Belt 4 Install 37 inch 940 mm drive belt over circulating pump pulley 74565 a a 37 inch 940 mm Drive Belt ...

Page 337: ...d Lockwashers Tighten securely 6 Attach power steering pump bracket to engine Torque bolt to 30 lb ft 41 N m 74559 a a 1 1 4 inch 32 mm Long Bolt Without Closed Cooling 1 1 2 inch 38 mm Long Bolt With Closed Cooling 7 Attach power steering pump brace to pump 74560 a 7 8 inch 22 mm Long Bolt and Washer 8 Install 37 inch 940 mm drive belt over pump pulley 74561 a a 37 inch 940 mm Drive Belt 9 Adjust...

Page 338: ...4566 a Breaker Points Ignition a Hydraulic Hose Routing 11 DDIS AND EST MODELS Install fluid cooler and tighten hose clamp screw securely 74569 a a Clamp Screw Tighten Securely 12 BREAKER POINTS IGNITION MODELS Install fluid cooler and tighten screw securely 74585 b a a 1 inch 25 mm Bolts b Power Steering Fluid Cooler ...

Page 339: ...l water hoses to power steering fluid cooler and tighten clamps securely 74569 a a Hose Clamps INSTALLATION 1 Using hose clamp install new hose on back of pump Tighten clamp securely 72848 b a a Hose Clamp b Hose 2 Using hose clamp install hose on fluid cooler Tighten clamp securely 73579 a c b a Fluid Cooler b Hose Clamp c Hose ...

Page 340: ...hose clamp and remove hose from fluid cooler 73579 a c b a Fluid Cooler b Hose Clamp c Hose 2 Remove large fitting from control valve at tran som Remove hose 72026 a Earlier Style Control Valve a Large Fitting 73786 a Later Style Control Valve INSTALLATION CAUTION Route hoses exactly as shown below This will help avoid stress on the hose fittings and will help avoid kinks in the hoses IMPORTANT Be...

Page 341: ...5 lb ft 27 34 N m 72026 a a Large Fitting Later Style Control Valve Torque fittings to 23 lb ft 31 N m 73786 4 Route hose along flywheel housing and secure with J clamp s provided 5 Using hose clamp install hose on fluid cooler Tighten clamp securely b 73579 a c a Fluid Cooler b Hose Clamp c Hose 6 Fill and air bleed system Refer to Section 1B Maintenance see Table of Contents ...

Page 342: ...ower steering pumps that affords both accessibility and easy visual inspection of fluid level Location must be at least 6 in 152 mm higher than pump cap to allow fluid from reservoir to flow freely to pumps preferably on transom or on forward engine compartment wall b Install reservoir mounting bracket with hard ware supplied 71402 a a Measurement 6 In 152 mm Minimum 2 Position bottle reservoir in...

Page 343: ...th hose clamps Tighten securely 6 Secure hoses with Sta Straps to keep them be low reservoir fluid level line and away from heat and moving parts 72857 b d a c e a Power Steering Pump Cap Port and Starboard b Hose to Reservoir c Hose Clamp d Sta Straps e Bend Radius Port and Starboard 72858 b a c b a Reservoir b Hoses from Pumps c Hose Clamps Installing Priority Valve NOTE Priority valve mounting ...

Page 344: ...4 N m 72860 c d a b a Bolt and Washer b Washer and Nut Not Shown in This View c Bracket d Priority Valve NOTE Engines with power steering are equipped with a hose that is connected to the power steering fluid cooler A fitting on the other end of the hose would normally be connected to the power steering control valve These hoses are not used and are re placed with bulk hose supplied with priority ...

Page 345: ...Steering Fluid Cooler b Hose c Hose Clamp 72862 b c a c b a Priority Valve b Hose c Hose Clamp 7 Install return hose large fitting on one end only from kit to power steering control valve Route hose to priority valve cut hose to length and con nect to fitting on priority valve Secure with hose clamp Tighten securely 72863 b a a Power Steering Control Valve b Hose Fitting 72864 b c a a Priority Val...

Page 346: ...a a Power Steering Control Valve b Hose Fitting 72866 b a a Priority Valve b Hose Fitting 9 Connect No 1 starboard engine pressure hose from pump to inverted flare fitting marked by 1 on priority valve Connect No 2 port pressure hose from pump to inverted flare fitting marked by 2 on priority valve Secure with hose clamps Tighten securely 72867 b c a a Priority Valve b No 1 Starboard Pressure Hose...

Page 347: ...Fill bottle reservoir and repeat this process for the other pump 14 Double check both caps to ensure they are both tight Maintenance Maintenance inspection is the owner s responsibility and must be performed at the following intervals Normal Service Every 50 hrs of operation or 60 days whichever comes first Severe Service Every 25 hrs of operation or 30 days whichever comes first NOTE Operation in...

Page 348: ... 2 Priority Valve and Mounting Bracket 3 Power Steering Control Valve 4 Power Steering Pump 5 Power Steering Fluid Cooler a Pressure Hose Fitting on Both Ends Supplied in Kit b Return Hose Fitting on One End Supplied in Kit c Return Hose from Pump Cut from Bulk Hose Supplied d Pressure Hose from Pump e Return Hose from Pump f Gravity Feed Hose Cut from Bulk Hose Supplied ...

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