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Briggs & Stratton 405777 Series Manual Download Page 27

3

 

4

5. Remove screws and choke plate.

a. Remove choke shaft. Discard seal.

Fig. 8 

−

 Remove Choke Shaft

CHOKE

PLATE

SEAL

6. Remove nozzle body. Discard gasket.

Fig. 9 

−

 Remove Nozzle Body

NOZZLE

BODY

GASKET

7. Mark throttle plates before removing so that they may be

re-installed in the same position. Sides of throttle plate are

beveled.

8. Remove screws, throttle plates and throttle shaft with

seal.

a. Discard seal.

This completes the carburetor disassembly procedure.

Fig. 10 

−

 Remove Throttle Shaft

THROTTLE

PLATES

SEAL

CARBURETOR CLEANING RECOMMENDATIONS

WEAR

 suitable skin protection when using clean-

ers. 

FOLLOW

 instructions on container.

1. Disassemble carburetor.

2. Remove and discard all old gaskets, seals and sealing

material.

3. Use commercial carburetor cleaning solvents (such as

Briggs & Stratton Spray Cleaner, Part #100041 or

100042) to clean carburetor parts and body.

4. When cleaning non-metallic parts (plastic, nylon, Min-

lon

™

, etc.), do not leave in commercial carburetor cleaner

more than 15 minutes.

Note:

Parts containing rubber, such as seals, “O” rings,

inlet needles, seats or pump diaphragms should

never be placed in commercial carburetor cleaner.
To prevent eye injury, always wear eye protection

when using compressed air.

5. Use only compressed air (blowing in both directions) to

clean out all openings and passages.

Note: Do not 

use wires, drills or any other devices to

clean out metering holes or passages.

TSM

Summary of Contents for 405777 Series

Page 1: ...TSM ...

Page 2: ...N REPAIR Section 10 CRANKSHAFT CAMSHAFT Section 11 PISTON RINGS CONNECTING ROD INSPECTION ASSEMBLY Section 12 ENGINE ASSEMBLY Section 13 TABLE OF CONTENTS For Section Reference See Pages II through IV I Contact Troy s Service Manuals for all your Repair Service Manual needs We carry a full line of manuals for Briggs Stratton Tecumseh Kohler We also have Kawasaki Honda Yamaha Auto Truck and more We...

Page 3: ...ng Recommendation Also See Checking Battery 7C Bearings 10 Checking Installation Removal Breather 8 Checking Installation Removal Camshaft Checking 11 Installation 13 Removal 13 Carburetor 3 Adjustment Anti Afterfire System Assembly Disassembly Remove Carburetor Controls 4 Charging System See Alternators 7C Coils See Armature 2 Compression Testing 1 Connecting Rod Checking 12 Installation 13 Crank...

Page 4: ...3 Fuel Recommendations 1 Fuel Pump 3 General Information 1 Governor 4 Adjustment Governed Idle Also See Governed Idle Adjustment 3 13 Ground Wire Harness 2 Ignition 2 Specifications Also See Check Ignition 1 Keyswitch Testing 2 6 Maintenance Schedule 1 Muffler Supplied By Equipment Manufacturer Oil Drain 1 Oil Fill 1 8 Oil Filter 1 Oil Pressure Switch 8 Oil Pump 4 8 Oil Recommendations 1 8 Oil Sea...

Page 5: ...stment 4 Starters Electric 6 Assemble Disassemble Starter Assemble Disassemble Starter Drive Keyswitch Testing Replace Brushes Test Equipment Testing Troubleshooting Stop Switch See Ground Wire Harness 2 Fastener And Torque Specifications 1 Troubleshooting 1 Valves 5 Adjust Valve Clearances Refacing Seals Seats Valves Installation Removal TSM ...

Page 6: ...031 17 8594 7 32 0 2188 5 5562 23 32 0 7188 18 2562 15 64 0 2344 5 9531 47 64 0 7344 18 6531 1 4 0 2500 6 3500 3 4 0 7500 19 0500 17 64 0 2656 6 7469 49 64 0 7656 19 4469 9 32 0 2812 7 1438 25 32 0 7812 19 8438 19 64 0 2969 7 5406 51 64 0 7969 20 2406 5 16 0 3125 7 9375 13 16 0 8125 20 6375 21 64 0 3281 8 3344 53 64 0 8281 21 0344 11 32 0 3438 8 7312 27 32 0 8438 21 4312 23 64 0 3594 9 1281 55 64 ...

Page 7: ...1495 24 152 23 154 5 32 1562 22 157 21 159 20 161 19 166 18 1695 11 64 1719 17 173 16 177 15 180 14 182 13 185 3 16 1875 12 189 11 191 10 1935 9 196 8 199 7 201 13 64 2031 6 204 5 2055 4 209 3 213 7 32 2188 2 221 1 228 A 234 15 64 2344 B 238 C 242 D 246 E 1 4 250 F 257 G 261 17 64 2656 H 266 I 272 J 277 K 281 9 32 2812 L 290 M 295 19 64 2969 N 302 5 16 3125 O 316 P 323 21 64 3281 Q 332 R 339 11 32...

Page 8: ...e Spark Plugs 5 Air Cleaner Maintenance 6 Remove Combustion Chamber Deposits 6 TROUBLESHOOTING Systematic Check 6 Check Ignition With Electric Starter 7 Check Ignition Engine Running 7 Checking For Fouled Spark Plug 7 Check Carburetion 8 Check Compression 8 Cylinder Leakdown Test 8 Cylinder Balance Test 8 Equipment Affecting Engine Operation 9 FASTENER SPECIFICATIONS 10 COMMON SPECIFICATIONS 11 ST...

Page 9: ...ed before stopping DO NOT tamper with governor springs links or other parts to increase engine speed Run engine at speed set for equip ment manufacturer DO NOT check for spark with spark plug removed Use an approved tester DO NOT run engine without blower housing or other safety shields removed when doing repairs DO NOT crank engine with spark plug removed If engine is flooded place throttle in FA...

Page 10: ... Shaft Pulsa Jet Carburetor Pneumatic or Mechanical Governor 0 Plain Bearing DU Non Flange Mount 1 Plain Bearing Flange Mounting 2 Sleeve Bearing Flange Mounting Splash Lube 3 Ball Bearing Flange Mounting Splash Lube 4 Ball Bearing Flange Mounting Pressure Lubrication on Horizontal Shaft 5 Plain Bearing Gear Reduction 6 to 1 CW Rotation Flange Mounting 6 Plain Bearing Gear Reduction 6 to 1 CCW Rot...

Page 11: ...SH gasoline minimizes gum deposits and also will ensure fuel volatility tailored for the season in which the engine will be operated Lubrication Oil has four purposes It cools cleans seals and lubri cates During normal operation small particles of metal from the cylinder walls pistons bearings and combustion deposits will gradually contaminate the oil Dust particles from the air also contaminate t...

Page 12: ...IL DRAIN PLUG Clean Cooling System Grass particles chaff or dirt can clog the air cooling system especially after prolonged service in cutting dry grass or very dirty air Continued operation with a clogged cooling system can cause severe overheating and possible engine damage Remove rotating screen and blower housing Fig 2 Cover intake elbow to prevent dirt entering carburetor Clean all debris and...

Page 13: ...artridge Remove air cleaner cover Fig 4 a Remove and inspect cartridge Replace if dam aged or dirty b NOTE DO NOT use petroleum solvents such as kerosene to clean paper cartridge They may cause cartridge to deteriorate DO NOT oil paper cartridge DO NOT use pressurized air to clean or dry paper cartridge c Reinstall cartridge and air cleaner cover Fig 4 NOTE Be sure tabs on blower housing are engag...

Page 14: ...Fig 5 Checking for Spark SPARK PLUG LEAD SPARK PLUG If spark does not occur look for Improperly operating interlock system Shorted equipment stop switch wire Two closed diodes in ground wire harness Incorrect armature air gap Armature failure Check Ignition Engine Running If engine runs but misses during operation a quick check to determine if ignition is or is not at fault can be made by installi...

Page 15: ...cylinder and record that reading The difference between both cylinders should not exceed 25 More than 25 indicates loss of compression in the cylinder with lower pressure See example Example Cyl 1 Cyl 2 Diff Diff Eng 1 65 PSI 60 PSI 5 PSI 7 6 Eng 2 75 PSI 55 PSI 20 PSI 26 7 If compression is poor look for Loose cylinder head bolts Blown head gasket Burned valves valve seats and or loose valve seat...

Page 16: ...roblem with engine operation such as hard starting vibration etc may be the fault of the equipment powered rather than the engine itself Since many types of equipment are powered by Briggs Stratton engines it is not possible to list all of the various conditions that may exist Listed are the most common effects of equipment problems and what to look for as the most common cause Hard Starting or Wi...

Page 17: ...lywheel 1 1 4 150 ft lbs 203 0 Nm Governor Control Bracket 3 8 80 in lbs 9 0 Nm Governor Nut 7 16 130 in lbs 15 0 Nm Head Bolts 1 2 220 in lbs 25 0 Nm Intake Air Horn 7 16 45 in lbs 5 0 Nm Intake Manifold to cyl head 3 8 T 30 80 in lbs 9 0 Nm Oil Drain Plug 3 8 Square Drive internal 125 in lbs 14 0 Nm Oil Pump Cover T 30 50 in lbs 6 0 Nm Rocker Arm 8 mm 100 in lbs 11 0 Nm Rocker Arm Lock Nut 13 mm...

Page 18: ...275 15 93 mm Cylinder Head Valve Guide 2374 2383 6 03 6 05 mm 240 6 09 mm Valve Stem 2345 235 5 97 5 98 mm 233 5 92 mm Sump Main Bearing PTO 1 6268 1 6275 41 32 41 34 mm 1 629 41 37 mm Cam Bearing PTO 6255 626 15 88 15 90 mm 6275 15 93 mm Crankshaft Crankpin 1 4982 1 499 38 05 38 07 mm 1 4965 38 01 mm Magneto Journal 1 3776 1 3784 34 99 35 01 mm 1 376 34 95 mm PTO Journal 1 6241 1 6249 41 25 41 27...

Page 19: ... 30 mm 19203 150 203 0 SPECIFICATIONS FOR ALL INTEK OHV V TWIN CYLINDER ENGINE MODELS See Section 1 For Spark Plug Maintenance And Specifications Flywheel Holder Part No 19489 or 19433 GENERAL INFORMATION Briggs Stratton OHV V Twin engines use MAGNETRON ignition an ignition armature with a self contained transistor mod ule no moving parts Two MAGNETRON ignition armatures are used with a flywheel c...

Page 20: ...re in place 4 Repeat for second armature Fig 2 Installing Armature WIRE ROUTING Adjust Armature Air Gap 1 Rotate flywheel until magnet is under armature lamina tions 2 Place thickness gauge 008 012 0 20 30 mm be tween magnet and armature laminations Fig 3 3 Loosen mounting screw so magnet will pull armature down against thickness gauge a Torque screws to 25 in lbs 3 0 Nm 4 Rotate flywheel to remov...

Page 21: ...en fins or keyway damage Also check crankshaft keyways and taper for damage Fig 6 Replace crank shaft if damaged Fig 6 Check Flywheel And Crankshaft CHECK Install Flywheel CLEAN flywheel and crankshaft taper removing all oil dirt or grease 1 Assemble flywheel to crankshaft and align keyways 2 Insert flywheel key into crankshaft 3 Assemble fan and retainer to flywheel Fig 7 a Torque screws to 140 i...

Page 22: ...7 or 19390 In the Diode Test position the meter will display the forward voltage drop across the diode s If the voltage drop is less than 0 7 volts the meter will Beep once as well as display the voltage drop A continuous tone indicates continuity shorted diode An incomplete circuit open diode will be displayed as OL 1 Insert RED test lead into receptacle in meter 2 Insert BLACK test lead into rec...

Page 23: ...Open Diodes SWITCH ON CAUSE Won t Run No Spark Engine Runs Both Cylinders Engine Runs On 1 Cylinder SWITCH OFF Shuts Off OK DIODE GROUND WIRE HARNESS EQUIPMENT SWITCH DIODE FAILURE DIAGNOSIS DIODE ENGINE HARNESS CARBURETOR SOLENOID ENGINE WIRING HARNESS DIAGRAM EQUIPMENT HARNESS CONNECTOR RAISED RIB ON CONNECTOR INDICATES GROUND SIDE _ 6 5 4 3 2 1 TSM ...

Page 24: ... Wear 5 ASSEMBLE CARBURETOR 5 ASSEMBLE CARBURETOR TO INTAKE MANIFOLD 7 INSTALL INTAKE MANIFOLD AND CARBURETOR 7 ADJUST GOVERNOR Static Governor Adjustment 8 Dynamic Governor Adjustment 8 Governed Idle Adjustment 9 Adjust Top No Load Speed FUEL SHUT OFF SOLENOID 10 TESTING SOLENOID 10 TESTING EQUIPMENT WIRING 10 TESTING ENGINE WIRING 10 FUEL PUMP 11 Inline Fuel Filter Service 11 Section Contents TS...

Page 25: ...le control cables 2 Remove air cleaner cover cartridge and pre cleaner 3 Remove rotating screen and blower housing a Disconnect breather tube at air horn Fig 1 Remove Blower Housing 4 Disconnect fuel line at carburetor 5 Disconnect wiring connector at solenoid 6 Remove intake manifold screws a Disconnect governor link from governor lever b Remove intake manifold and carburetor assem bly c Discard ...

Page 26: ... 19458 14 mm or 19459 16 mm b Remove fixed main jet Note Use care when removing solenoid to prevent damage to fixed main jet and housing Fig 5 Remove Fuel Solenoid MAIN JET MAIN JET HOUSING SOLENOID 3 Remove float hinge pin float and inlet needle 4 Remove emulsion tube body and gasket Discard gasket Fig 6 Remove Float EMULSION TUBE BODY INLET NEEDLE FLOAT Fig 7 Remove Cover Plate COVER PLATE Remov...

Page 27: ...W instructions on container 1 Disassemble carburetor 2 Remove and discard all old gaskets seals and sealing material 3 Use commercial carburetor cleaning solvents such as Briggs Stratton Spray Cleaner Part 100041 or 100042 to clean carburetor parts and body 4 When cleaning non metallic parts plastic nylon Min lon etc do not leave in commercial carburetor cleaner more than 15 minutes Note Parts con...

Page 28: ...etor body is worn replace carburetor Fig 12 Checking Throttle And Choke Shaft ASSEMBLE CARBURETOR When assembling carburetor use new seals and gaskets 1 Assemble new seal to throttle shaft and insert into car buretor body Important Install one throttle plate at a time Check throttle shaft for freedom of operation before installing other throttle plate Note Use LOCTITE 222 on screw threads Fig 13 I...

Page 29: ...rbu retor body a Install choke plate Note Use LOCTITE 222 on screw threads Fig 16 Install Choke Shaft CHOKE PLATE SEAL 5 Install emulsion tube body with new gasket a Tighten screw securely Fig 17 Install Emulsion Tube Body EMULSION TUBE BODY 6 Assemble inlet needle to float and install float a Assemble bowl gasket to body Fig 18 Install Float INLET NEEDLE FLOAT TSM ...

Page 30: ...arburetor from outside in Fig 20 Assemble Governor And Choke Link INSTALL CHOKE LINK FROM OUTSIDE IN INSTALL GOV ERNOR LINK FROM INSIDE OUT ASSEMBLE CARBURETOR TO INTAKE MAN IFOLD 1 Connect choke link to choke lever and assemble carbu retor and spacer to intake manifold with new gaskets a Use Torx socket Tool 19455 and torque studs to 65 in lbs 7 0 Nm 2 Assemble air horn to carburetor with new gas...

Page 31: ...Loosen governor lever nut Rotate governor control swivel counter clockwise as far as it will go wide open throttle and hold in this position 2 Rotate governor shaft clockwise as far it will go Fig 24 a Torque governor nut to 130 in lbs 15 0 Nm 3 Install throttle and choke control cables and check for proper operation Fig 24 Adjust Governor GOVERNOR SHAFT CONTROL SWIVEL Dynamic Governor Adjustment ...

Page 32: ...IDLE TANG 4 With engine running at governed idle RPM bend throttle restrictor tang so that tang just contacts gover nor lever Fig 28 Fig 28 Adjusting Throttle Restrictor THROTTLE RESTRICTOR Adjust Top No Load Speed Refer to Service Engine Sales Microfiche MS 6225 or Service Engine Sales Manual MS 4052 for Top No Load RPM by engine model and type number 1 Move equipment control to FAST position and...

Page 33: ...NT WIRING 1 With keyswitch in OFF position disconnect equipment wiring harness connector from engine wiring harness 2 Attach red meter test lead into equipment wiring harness connector side opposite raised rib 3 Attach black test lead to a good ground Fig 31 4 Turn keyswitch to ON position a Meter should display battery voltage at connector If meter does not display battery voltage problem is with...

Page 34: ...sembly only Replace fuel lines and vacuum pulse line if stiff and brittle Note An air leak at the fuel pump pulse line hose connections will result in improper fuel flow Fig 33 Fuel Pump Inline Fuel Filter Service Replace inline fuel filter yearly or every 100 hours whichever occurs first Replace filter if dirt or water are present See illustrated parts list for correct fuel filter Fig 34 Exploded...

Page 35: ...s to close the throttle The engine speed at which these two forces balance is called the governed speed The governed speed can be varied by changing the governor spring or governor spring tension Governor spring tension adjustment must not exceed 200 RPM or the governor spring must be replaced If a governor spring must be replaced consult the appropriate Illustrated Parts List Select the proper go...

Page 36: ...Control Wire Dimensions 2 1 8 MIN 54 MM 1 3 8 MIN TRAVEL 35 MM Speed Control Wire Adjustment 1 Loosen control casing clamp at governor control brack et 2 Move speed control lever to FAST position 3 Move control casing and wire in direction shown by ar row until governor control swivel is at end of travel Fig 4 4 Tighten casing clamp screw Fig 4 Control Wire Adjustment CASING CLAMP SCREW THROTTLE S...

Page 37: ... a Remove governor lever from shaft Fig 6 Fig 6 Remove Governor Lever GOVERNOR LEVER NUT 2 Remove oil pump Fig 7 a Remove oil pump cover b Remove inner rotor c Remove outer rotor d Remove drive shaft Fig 7 Remove Oil Pump A B C D 3 Remove sump and discard gasket Fig 8 a Remove governor gear and thrust washer Fig 8 Remove Sump GOVERNOR GEAR 4 Remove governor shaft from sump Fig 9 a Remove lower E r...

Page 38: ... for burrs or nicks Fig 12 2 Check flyweights for damage or wear 3 Check governor cup and thrust washer for damage or wear 4 Check governor gear shaft and bearings for damage or wear Replace as required Fig 12 Check Governor Gear And Shaft Install Governor Shaft Bushing Lubricate new bushing and governor shaft with engine oil 1 Assemble governor shaft to sump to act as a pilot for bushing Do not i...

Page 39: ...nstall Sump 1 5 9 6 7 2 4 8 10 3 3 Lubricate oil pump components with engine oil and as semble to sump Fig 16 Make sure drive shaft is en gaged in camshaft a Install drive shaft b Install inner rotor c Install outer rotor d Install oil pump cover with new O ring e Torque screws to 50 in lbs 6 0 Nm Fig 16 Install Oil Pump A B C D 4 Reassemble governor lever to governor shaft Fig 17 DO NOT tighten n...

Page 40: ...r personal injury Static Governor Adjustment 1 With governor lever nut loose rotate governor control swivel counter clockwise as far as it will go wide open throttle and hold in this position 2 Rotate governor shaft clockwise as far it will go Fig 20 a Torque governor nut to 130 in lbs 15 0 Nm Fig 20 Adjust Governor GOVERNOR SHAFT CONTROL SWIVEL Dynamic Governor Adjustment ALL ADJUSTMENTS MUST BE ...

Page 41: ... IDLE TANG 4 With engine running at governed idle RPM bend throttle restrictor tang so that tang just contacts gover nor lever Fig 24 Adjust Top No Load Speed Refer to Service Engine Sales Microfiche MS 6225 or Service Engine Sales Manual MS 4052 for Top No Load RPM by engine model and type number 1 Move equipment control to FAST position and check RPM a Bend tang to obtain correct RPM Fig 25 Note...

Page 42: ...head Valve Train Page REMOVE CYLINDER HEAD 2 DISASSEMBLE CYLINDER HEAD 4 INSPECT AND REPAIR Cylinder Head 5 Valve Guides 5 Valves 5 ASSEMBLE CYLINDER HEAD 6 INSTALL CYLINDER HEAD 8 ADJUST VALVES 8 REASSEMBLE 9 ADJUST GOVERNOR 10 Section Contents TSM ...

Page 43: ...t air horn a Disconnect fuel solenoid wires at carburetor b Remove intake manifold and carburetor c Disconnect governor link from governor lever Fig 2 Remove Intake Manifold And Carburetor B A C 3 Loosen governor lever nut 4 Remove governor control bracket and governor lever Fig 3 Remove Governor Lever And Control Bracket NUT GOVERNOR LEVER CONTROL BRACKET 5 Remove No 1 cylinder shield with fuel p...

Page 44: ...iscard gaskets Fig 6 Remove Valve Covers 8 Remove rocker arms and push rods Fig 7 Note Mark push rods so that they may be reassembled in their original position Intake valve push rods are aluminum Fig 7 Remove Rocker Arms And Push Rods 9 Remove cylinder heads and discard gaskets Fig 8 Fig 8 Remove Cylinder Head TSM ...

Page 45: ...shop rag or short section of rubber fuel line under valves inside combustion chamber to hold valve in place while compressing spring Thread rocker arm support screw into cylinder head a few turns and compress spring with valve spring compressor Tool 19347 Remove the following a Valve spring retainer locks b Valve spring retainer c Valve spring d IN and EX valve Fig 10 Remove Valves 2 Remove and di...

Page 46: ...placed Fig 13 Check Valve Guide Bushing REJECT GAGE 3 Valve seats may be reconditioned using valve seat cut ter tool 19547 If valve seat is wider than dimension shown in Fig 14 a narrowing cutter should be used to ensure that contact area of valve seat is centered on face of valve a Use a 60 cutter to narrow seat from bottom and a 15 cutter to narrow seat from top Fig 18 Note If valve seat is loos...

Page 47: ...6 Measure Valve Stem Diameter 1 600 40 MM Fig 17 Cylinder Head Components ASSEMBLE CYLINDER HEAD 1 Cylinder Head 2 Cylinder Head Gasket 3 Valve Spring Retainer Locks 4 Valve Spring Retainer 5 Valve Spring 6 Valve 7 Valve Stem Seal 8 Rocker Arm 9 Rocker Arm Support 10 Rocker Arm Support Screw 11 Push Rod 3 4 5 6 7 1 2 11 10 8 9 TSM ...

Page 48: ...TAWAY VIEW 2 Install valves Note Lightly coat valve stems with Valve Guide Lubricant 93963 before installing valves Fig 19 Install Valves 3 Install valve springs with valve spring compressor Tool 19347 Fig 20 Fig 20 Install Valve Springs 4 Assemble rocker arms and supports to cylinder head Fig 21 Apply Loctite 242 or similar sealant to threads a Torque screws to 100 in lbs 11 0 Nm Fig 21 Install R...

Page 49: ... Intake push rods are aluminum Fig 23 Install Cylinder Head Assembly 3 4 5 1 2 4 Compress valve springs and insert push rods into re cess in rocker arm adjustment screws Fig 24 Fig 24 Install Push Rods ADJUST VALVES 1 Set No 1 cylinder at 1 4 6 4mm past TDC compres sion stroke a Adjust valves and check Fig 25 Valve Clearance cold IN and EX 005 0 13 mm b Torque jam nut and adjusting screw to 60 in ...

Page 50: ... in lbs 5 0 Nm Fig 27 Install Cylinder Shield 1 4 20 SCREW 10 24 SCREW 2 Install No 2 cylinder shield Fig 28 a Torque 1 4 20 screw to 80 in lbs 7 0 Nm b Torque 10 24 screw to 45 in lbs 5 0 Nm Fig 28 Install Cylinder Shield 1 4 20 SCREW 10 24 SCREW 3 Install governor control bracket and assemble gover nor lever to governor shaft DO NOT tighten nut at this time a Torque control bracket screws to 80 ...

Page 51: ...T GOVERNOR WARNING BEFORE STARTING or running en gine static adjustment of the governor must be completed Failure to make the static adjustments first could result in engine overspeeding which may result in engine damage property damage or personal injury Static Governor Adjustment 1 Rotate governor control swivel counter clockwise as far as it will go wide open throttle and hold in this position ...

Page 52: ...OTOR 5 Inspect Armature Commutator 6 Inspect Brushes 6 ASSEMBLE STARTER 6 Install Starter Motor 7 REPLACE RING GEAR 7 BATTERY INFORMATION 8 Installation 8 Checking Battery 8 Testing Battery 9 Battery Recommendations 9 Battery Cable Recommendations 9 Section Contents GENERAL INFORMATION The starter motor uses a gear type engagement method similar to an automobile starter When the starter motor is a...

Page 53: ...ing d Battery faulty or damaged e Incorrect rotation due to reversed motor polar ity all motors rotate counterclockwise viewed from pinion gear Starter Motor Spins But Will Not Stop a Defective starter switch TEST EQUIPMENT The following is a list of equipment recommended to test and repair starter motors Digital Multimeter The Digital Multimeter is available from your Briggs Stratton source of su...

Page 54: ...or strike with a steel hammer Starter motors contain two ceramic magnets which can be broken or cracked if the motor housing is hit deformed or dented Testing Starter Motor A fully charged 12 volt battery is required 1 The DC Shunt MUST be installed on the negative battery terminal as shown in Fig 6 2 Insert RED test lead into receptacle in meter and connect to RED post terminal on shunt 3 Insert ...

Page 55: ...or drive does not react properly inspect the helix and pinion gear for freedom of operation Fig 7 The pinion gear should be inspected for damaged teeth Pinion gear must move freely on helix The parts may be washed in a solvent such as Stanisol or Varsol Fig 7 Starter Drive Disassemble Starter Motor Drive WARNING TO PREVENT EYE INJURY always wear eye protection when removing C ring 1 Place counterb...

Page 56: ...of shaft Align one of the slots of Tool 19435 with open end of C Ring 5 Press or drive C Ring on until it snaps into groove in shaft Fig 10 Fig 10 Install C Ring C RING TOOL 19435 SLOT DISASSEMBLE STARTER MOTOR See Fig 11 for exploded view of starter motor To aid in reassembly scribe a mark on drive end cap and starter housing for alignment purposes 1 Remove thru bolts 2 Remove drive end cap assem...

Page 57: ... cleaned using an aerosol carburetor cleaner or compressed air The armature should be checked for shorts with a growler Fig 13 Inspect Commutator 1 230 MINIMUM Inspect Brushes The brushes should be checked for proper seating weak brush springs dirt oil or corrosion Brush spring pressure should be strong enough to ensure good brush contact with armature Check to be sure brushes are not sticking in ...

Page 58: ...e Install Starter Motor Install starter motor and torque screws to 140 in lbs 16 0 Nm Fig 17 Install Drive End Cap SPRING WASHER THRUST WASHER REPLACE RING GEAR File or grind off rivet heads from top side of flywheel Fig 18 Then drive out rivets with 3 16 punch Pry off old ring gear Carefully align holes in ring gear with holes in flywheel Use a flat plate and press on new ring gear Then fasten ne...

Page 59: ...snug DO NOT overtighten 3 Connect positive terminal to positive post FIRST to pre vent sparks from accidental grounding Tighten con nectors securely 4 Install protective cover over positive battery terminal ends 5 Then connect negative terminal to negative battery terminal Tighten connectors securely Fig 19 Typical 12 V Wiring Diagram ALTERNATOR SOLENOID STOP SWITCH STARTER MOTOR 12 VOLT BATTERY R...

Page 60: ...ers Tool 19368 Turn switch to START METER SHOULD DISPLAY 9 VOLTS OR MORE WHILE CRANKING ENGINE If less than 9 volts replace battery DO NOT CRANK STARTER for more than 15 SECONDS without allowing starter to COOL at least 2 MINUTES The starter motor could be damaged Battery Recommendations These battery size recommendations are based on minimum temperature expected and correct weight of oil being us...

Page 61: ...RNATOR 8 Alternator Output Test 8 Diode Test 8 Charging Circuit Red Wire 8 Lighting Circuit White Wire 9 5 9 AMP REGULATED ALTERNATOR 9 Alternator Output Test 9 Testing Regulator Rectifier 10 10 16 AMP REGULATED ALTERNATOR 10 Alternator Output Test 10 Test Regulator Rectifier 11 Testing Regulator Rectifier 10 Amp System 11 Testing Regulator Rectifier 16 Amp System 11 Regulator Rectifier With Charg...

Page 62: ...ulated 7 4 Tri Circuit Black Green 5 Amps DC Charging 5 Amps DC Lights 9 5 Regulated 5 Amp Black Green 1 5 Amps DC Charging Regulated 10 5 Regulated 9 Amp Black Green 1 9 Amps DC Charging Regulated 10 6 Regulated 10 Amp 2 Black Yellow 1 10 Amps DC Charging Regulated 11 6 Regulated 16 Amp 2 Black Yellow 1 16 Amps DC Charging Regulated 12 Alternator output is determined by flywheel alternator magnet...

Page 63: ...or Two diodes encased in wire harness Red and white output leads GREEN CONNECTOR ONE BLACK LEAD 5 AMPS DC TO LIGHTS WHITE LEAD TWO DIODES ENCASED IN WIRE HARNESS RED LEAD 5 AMPS DC TO BATTERY AND CLUTCH CIRCUIT STATOR ASSEMBLY Fig 4 Tri Circuit Stator 5 or 9 amp DC regulated for charging battery Alternator output 5 or 9 amp is determined by fly wheel alternator magnet size Uses same stator as Tri ...

Page 64: ...l Identification Intek OHV Twin Cylinder Flywheels have a single ring of magnets which provide the magnetic field for the various alternator systems There are two 2 sizes of alternator magnets The size of the magnet determines the alternator output Fig 7 Fig 7 Alternator Magnets ALTERNATOR MAGNETS Small Magnet 22 mm x 17 mm 7 8 x 21 32 Large Magnet 22 mm x 23 mm 7 8 x 29 32 Table 2 identifies the ...

Page 65: ...or Inline fuse blown if equipped Loose or corroded wires Open shorted or grounded wires between output connector and electric clutch Defective diode open or shorted red output lead side NOTE Battery will also not charge Defective electric clutch switch Open shorted or grounded clutch circuit Low magnetic flux or damaged alternator magnets TEST EQUIPMENT The following equipment is recommended to te...

Page 66: ...s unregulated and is rated at 3 amps The output rises from 2 amps at 2400 RPM to 3 amps at 3600 RPM Recommended battery sizes range from 30 ampere hour for warm temperature service to 50 ampere hour in coldest service WHEN CHECKING ALTERNATOR COMPONENTS MAKE THE TEST IN THE FOLLOWING SEQUENCE Alternator Output Test 1 Insert RED test lead into 10 A receptacle in meter 2 Insert BLACK test lead into ...

Page 67: ...0 A receptacle in meter 2 Insert BLACK test lead into receptacle in meter 3 Rotate selector to DC amps position 4 Attach RED test lead clip to DC output pin in connector Fig 13 Fig 13 Testing DC Output RED WIRE RAISED RIB ON CONNECTOR INDICATES DC OUTPUT PIN SIDE DC OUTPUT PIN AC OUTPUT PIN RED TEST LEAD TO DC OUTPUT PIN BLACK TEST LEAD POSITIVE BATTERY TERMINAL THE BATTERY MUST BE IN GOOD CONDITI...

Page 68: ...es with DC charging lead limiting the charging current to approximately 3 amps when the clutch is not engaged When the clutch is engaged the resistor is bypassed allowing full output to the battery and clutch NOTE The 1 OHM 20 WATT resistor is supplied by the equipment manufacturer The battery is not used for the lights so lights are available even if the battery is disconnected or removed Current...

Page 69: ...s a continuous tone diode is defec tive shorted Replace harness c If meter displays OL proceed to step 6 6 Reverse test leads a If meter Beeps once diode is installed back wards Replace harness b If meter still displays OL diode is defective open Replace harness Fig 18 Diode Testing Lighting Circuit BLACK LEAD RED LEAD A WHITE WIRE NOTE Service replacement diode harnesses are avail able 5 9 AMP RE...

Page 70: ...be 5 or 9 amps depending upon the alternator system being tested If battery voltage is at its maximum the amperage will be less 7 If no or low output is found be sure that regulator recti fier is grounded properly and all connections are clean and secure If there is still no or low output replace the regulator rectifier 10 16 AMP REGULATED ALTERNATOR The 10 or 16 amp regulated alternator system pr...

Page 71: ... upon battery voltage For example if the battery voltage was below 11 volts the output reading would be 10 amps If battery voltage is at its maximum the amperage will be less 7 If no or low output is found be sure that regulator rectifi er is grounded properly and all connections are clean and secure If there is still no or low output replace the regulator rectifier Testing Regulator Rectifier 16 ...

Page 72: ...t should light when the key switch is in the ON position engine not running With engine running the charging indicator light should go out indicating that the charging circuit is operating providing that battery voltage is above 12 volts The charge indicator light and all wiring is supplied by the equipment manufacturer See typical wiring diagram page 13 DC charging output values and test procedur...

Page 73: ...al on solenoid 6 To Alternator DC Output KEY SWITCH SOLENOID TAB TERMINAL RED WIRE DC OUTPUT BATTERY TERMINAL STARTER TERMINAL AC OUTPUT WIRES HEADLIGHT SWITCH Terminal No Function Switch Position Continuity 1 OFF 1 3 6 2 RUN 2 5 6 3 START 2 4 5 Key Switch Test TERMINAL 1 GROUNDED INTERNALLY TO KEY SWITCH CASE 5 4 3 2 1 TYPICAL 16 AMP REGULATED ALTERNATOR WIRING DIAGRAM 6 POLE SWITCH WITH CHARGE I...

Page 74: ...HARGE INDICATOR WIRE TERMINAL WHITE CONNECTOR JUMPER WIRE OUTPUT HARNESS Symptom Charge Indicator Light Stays On Engine Running NOTE Indicator light will remain on if battery voltage is below 12 volts 1 Check indicator light wiring a If wiring is grounded light will remain on when en gine is running b If wiring is OK replace regulator rectifier BATTERIES The battery is of the 12 volt lead acid wet...

Page 75: ...ELLS VARY BY MORE THAN 50 DO NOT EXCEED CHARGE RATE OF 1 10 AMPERE FOR EVERY AMPERE OF BATTERY RATING Consult battery manufacturer for charging recommendations Overcharging may cause battery failure a Use a taper charger automatically reduces charge rate b Fill battery cells with distilled water or tap water unless maintenance free type after charging for batteries that have been in service NOTE I...

Page 76: ...NGE OIL FILTER 2 OIL FILL TUBE AND DIPSTICK 3 CHECK PRESSURE SWITCH 3 CHECK OIL PRESSURE 3 CRANKCASE BREATHER Check Breather 4 Install Breather 4 DISASSEMBLE OIL PUMP 5 ASSEMBLE OIL PUMP 5 Section 8 Lubrication System Section Contents F 20 0 20 40 60 80 100 C 30 20 10 0 10 20 30 40 TEMPERATURE RANGE ANTICIPATED BEFORE NEXT OIL CHANGE 32 OIL RECOMMENDATIONS TSM ...

Page 77: ...d by the equipment manufacturer CHANGE OIL Change oil and filter after first 8 hours of operation Thereafter change oil and filter every 50 hours of operation Change oil and filter more often if engine is operated in dusty or dirty conditions or if engine is operated under heavy loads or high ambient air temperatures Remove oil drain plug and drain oil while engine is still warm Fig 1 Install and ...

Page 78: ...ld open no continuity when approximately 4 5 PSI 0 3 Bar is applied Replace the switch if test results are not to specification Fig 5 Checking Pressure Switch CHECK OIL PRESSURE 1 Oil level must be between the LOW and FULL mark on dipstick If oil level is low check for leaks and add to FULL mark 2 Remove pressure switch or 1 8 NPTF plug in oil filter adapter 3 Install oil pressure gauge Fig 6 4 St...

Page 79: ... screen blower housing and flywheel See Section 2 1 Disconnect breather tube from intake elbow remove three screws and breather Discard gasket 2 Check to see that reed valve is not deformed Fig 8 Note Reed valve must make a complete seal around vent hole 3 Remove oil vapor collector and retainer 4 Check collector for deterioration and replace if neces sary Fig 8 Checking Breather INSTALL BREATHER ...

Page 80: ...s and shaft for any obvious wear and or damage Fig 11 Replace as necessary If pump housing is worn or damaged the sump must be replaced Fig 11 Checking Oil Pump ASSEMBLE OIL PUMP 1 Lubricate oil pump components with engine oil and as semble to sump Fig 12 Make sure drive shaft is en gaged in camshaft a Install drive shaft b Install inner rotor c Install outer rotor d Install new O ring e Install o...

Page 81: ...e Disassembly SCREEN BLOWER HOUSING FAN FLYWHEEL ALTERNATOR BACKPLATE ARMATURE CYLINDER HEAD GOVERNOR LEVER CONTROL BRACKET CYLINDER AIR GUIDE STARTER MOTOR PUSH RODS PUSH RODS STOP SWITCH WIRING HARNESS 2 1 CYLINDER HEAD TSM ...

Page 82: ...9 2 BREATHER CYLINDER ROD PISTON GOVERNOR CAMSHAFT CRANKSHAFT SUMP OIL PUMP 2 ROD PISTON 1 TAPPETS SUMP TSM ...

Page 83: ...ltube and dipstick e Stop switch wiring harness f Breather and oil vapor collector g Alternator Fig 1 Remove Back Plate And Starter Motor E D A G C B F 2 Remove oil pump Fig 2 a Oil pump cover b Inner rotor c Outer rotor d Drive shaft Fig 2 Remove Oil Pump A B C D 3 Remove sump and discard gasket Fig 3 a Remove governor gear and thrust washer GOVERNOR GEAR Fig 3 Remove Sump 4 Rotate crankshaft and...

Page 84: ...sh connecting rod and piston assembly out of cylinder a Reassemble cap to rod to prevent interchanging 6 Repeat for other cylinder Fig 5 Remove Piston And Connecting Rod 7 Remove crankshaft CLEAN ALL SURFACES OF GASKET MATERIAL RE MOVE OIL SEALS AND THOROUGHLY CLEAN COM PONENTS IN SOLVENT ORGANIZE COMPONENTS KEEPING PARTS WHICH ARE AN ASSEMBLY TO GETHER Fig 6 Remove Crankshaft TSM ...

Page 85: ...d mounting surface for distortion with a straight edge Fig 1 If mounting surfaces are distorted more than 004 0 1 mm the cylinder must be replaced Fig 1 Checking Cylinder 2 Check cylinder bores for wear using telescoping gauge Tool 19404 and dial caliper Tool 19199 Standard Bore Size Model 405770 2 969 2 970 75 41 75 43 mm Model 445770 3 119 3 120 79 22 79 25 mm a Measure cylinder bore in 6 points...

Page 86: ...ng screws and fasten cylinder to a honing fixture Fig 3 Clamp honing fixture and cylinder securely in a vise at a convenient work height Place hone drive shaft in chuck of portable drill and tighten Cut a wood block and place inside cylinder to prevent hone from extending further than 3 4 to 1 19 mm to 25 mm below cylinder bore Place hone in middle of cylinder bore Tighten adjusting knob with fing...

Page 87: ...se thoroughly with hot running water Repeat washing and rinsing until all traces of honing grit are gone Honing grit is highly abrasive and will cause rapid wear to all of the internal components of the engine unless it is completely removed NOTE When cylinder and crankcase have been thoroughly cleaned use a clean white rag or napkin and wipe the cylinder bore If honing grit is present it will app...

Page 88: ...ig 8 a Install new oil seal with sealing lips facing in b Use cylinder support Tool 19227 and press oil seal until flush with cylinder Fig 8 Stake Bearing Check Camshaft Bearings Check camshaft bearings in cylinder and sump for damage or wear Reject Dimension 6275 15 93 mm If bearings are damaged or worn the cylinder or crankcase cover must be replaced Fig 9 Check Cam Bearings Check PTO Bearing Ch...

Page 89: ...unting surface Always lubricate sealing lips with engine oil to prevent damaging seal when installing crankshaft Fig 11 Install Oil Seal 9 16 1 2 15 16 8 15 16 3 15 16 4 15 16 11 32 Thru Hole 3 14 3 mm 12 7 mm 23 8 mm 100 mm 227 mm 125 4 mm 8 7 mm Material Wood 2 x6 x16 Long Cylinder Mounting Hardware Fasteners Required 3 Crankcase Cover Screws 3 Flat Washers 5 16 I D 16 406 mm 6 152 4 mm Honing F...

Page 90: ...ay re ground for 020 undersize connecting rods Fig 2 See illustrated parts list for part number See crankshaft grinding dimensions Crankshaft Grinding Dimensions Dim A Dim R Dim T 1 4782 1 479 37 54 37 56 mm 170 180 4 32 4 57 mm 1 4435 1 4465 36 66 36 74 mm Checking Cam Shaft Inspect gear teeth lobes and journals for wear and nicks Fig 3 Check oil galleries for blockage or obstructions Camshaft jo...

Page 91: ... or ridge at the top of the cylinder bore This will prevent breaking the rings when removing the piston and connecting rod from the engine Remove the connecting rod cap Push the piston and connecting rod out through the top of the cylinder Measure cylinder bores before checking pistons and rings See Section 10 If cylinder bore s require re sizing it will not be necessary to check pistons and rings...

Page 92: ...ring the piston should be checked 1 Check side clearance of ring grooves using NEW rings Fig 3 If a 005 0 12 mm feeler gauge can be inserted the ring groove is worn The piston must be replaced Fig 3 Check Ring Grooves NEW PISTON RING 2 Check ring end gap Fig 4 a Clean carbon from end of rings and insert approxi mately 1 25 mm into cylinder Reject Dimension all 030 0 76 mm Fig 4 Checking Ring End G...

Page 93: ...arings CRANKPIN BEARING PISTON PIN BEARING ASSEMBLE PISTON AND CONNECTING ROD Lubricate parts with engine oil and assemble 1 piston and connecting rod Fig 8 1 Arrow on piston must face flywheel side 2 Number 1 on connecting rod must face PTO side op posite arrow on piston a Install piston pin locks with needle nose pliers Fig 8 Assemble 1 Rod And Piston 1 ARROW TOWARD FLYWHEEL SIDE Lubricate parts...

Page 94: ... may be installed with either side up Fig 10 Piston Ring Installation Model 405700 TOP CENTER OIL COIL EXPANDER WIRE ASSEMBLE PISTON RINGS TO PISTON Models 445700 1 Install piston rings using ring expander Tool 19340 Fig 11 a Install oil ring coil expander making sure wire is in serted fully into coil b Install oil ring c Install center compression ring then top compres sion ring with ID mark up F...

Page 95: ...ST VALVES 5 INSTALL CYLINDER SHIELDS 6 INSTALL GOVERNOR CONTROL BRACKET 6 INSTALL INTAKE MANIFOLD AND CARBURETOR ASSEMBLY 6 INSTALL BLOWER HOUSING 7 ADJUST GOVERNOR Static Governor Adjustment 7 Dynamic Governor Adjustment 7 Governed Idle Adjustment 8 Adjust Top No Load Speed 8 Section Contents INSTALL CRANKSHAFT Lubricate mag bearing and lips of oil seal with engine oil and install crankshaft Fig ...

Page 96: ...ling Piston And Connecting Rod ARROW FLYWHEEL SIDE P T O SIDE ARROW TOWARD FLYWHEEL SIDE 4 Assemble connecting rod cap to rod with match marks aligned Fig 4 a Torque screws to 100 in lbs 11 0 Nm 5 Rotate crankshaft two revolutions to check for binding Rod should also be free to move sideways on crankpin Repeat for 2 cylinder Note The number 1 on 1 connecting rod and the number 2 on 2 connecting ro...

Page 97: ...stall oil pump cover with new O ring e Torque screws to 50 in lbs 6 0 Nm Fig 7 Assemble Oil Pump A B C D E GENERAL ASSEMBLY 1 Install armatures and ground wire assembly Note Push armatures away from crankshaft as far as they will go and temporarily tighten screws 2 Install air guide a Torque screws to 45 in lbs 5 0 Nm 3 Install alternator a Torque screws to 20 in lbs 2 0 Nm Fig 8 Install Armatures...

Page 98: ...o 55 in lbs 6 0 Nm Fig 11 Install Starter Motor SCREWS STARTER MOTOR INSTALL FLYWHEEL CLEAN flywheel and crankshaft taper removing all oil dirt or grease 1 Assemble flywheel to crankshaft and align keyways 2 Insert flywheel key into crankshaft 3 Assemble fan and retainer to flywheel Fig 12 a Torque screws to 140 in lbs 16 0 Nm Fig 12 Install Fan And Retainer RETAINER FAN 4 Install washer and flywh...

Page 99: ... cylinder block 2 Install cylinder head assembly Fig 15 a Torque head bolts in sequence shown to 220 in lbs 25 0 Nm 3 Install push rods Make sure push rods are inserted in recess in tappets Note Intake push rods are aluminum Fig 15 Install Cylinder Head 3 4 5 1 2 4 Compress valve springs and insert push rods into re cess in rocker arm adjustment screws Fig 16 Fig 16 Insert Push Rods ADJUST VALVES ...

Page 100: ...24 SCREW INSTALL GOVERNOR CONTROL BRACKET 1 Install governor control bracket and assemble governor lever to governor shaft Fig 20 DO NOT tighten nut at this time a Torque control bracket screws to 80 in lbs 7 0 Nm Fig 20 Install Governor Control Bracket TORQUE TO 80IN LBS 6 8NM DO NOT TIGHTEN NUT INSTALL INTAKE MANIFOLD AND CARBURE TOR ASSEMBLY 1 Install intake manifold and carburetor assembly usi...

Page 101: ... clockwise as far as it will go wide open throttle and hold in this position 2 Rotate governor shaft clockwise as far it will go Fig 23 a Torque governor nut to 130 in lbs 15 0 Nm 3 Install throttle and choke control cables and check for proper operation 4 Install exhaust manifold a Torque screws to 140 in lbs 16 0 Nm Note Exhaust manifold and exhaust system supplied by equipment manufacturer Fig ...

Page 102: ... IDLE TANG 4 With engine running at governed idle RPM bend throttle restrictor tang so that tang just contacts gover nor lever Fig 27 Fig 27 Adjust Throttle Restrictor THROTTLE RESTRICTOR Adjust Top No Load Speed Refer to Service Engine Sales Microfiche MS 6225 or Service Engine Sales Manual MS 4052 for Top No Load RPM by engine model and type number 1 Move equipment control to FAST position and c...

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