Yamaha EK25BMH Page 109 Service Manual Download

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CYLINDER HEAD

POWR

5-20

CHECKING THE CYLINDER HEAD

1. Check:

•

Combustion chamber

Carbon deposits

→

Clean.

•

Water jacket

Mineral deposits/rust

→

Clean.

CAUTION:

Do not scratch the contacting surface of the
cylinder head and cylinder head cover.

2. Measure:

•

Cylinder head warpage

(use a straightedge and thickness
gauge)
Out of specification

→

Resurface/

replace.

Resurfacing steps

(1) Place a 400 – 600 grit wet sandpaper on

the surface plate.

(2) Resurface the cylinder head by moving

it in a figure-eight motion along the
sandpaper.

NOTE:

Rotate the cylinder head several times to
ensure an even surface.

Warpage limit

0.1 mm (0.004 in)

Summary of Contents for EK25BMH

Page 1: ...290404 EK25BMH 69T 28197 ZA 11 S S S SE E E ER R R RV V V VIIIIC C C CE E E E M M M MA A A AN N N NU U U UA A A AL L L L ...

Page 2: ...e or unfit for use Because Yamaha has a policy of continuously improving its products models may differ in detail from the descriptions and illustrations given in this publication Use only the latest edi tion of this manual Authorized Yamaha dealers are notified periodically of modifications and significant changes in specifications and procedures and these are incorporated in succes sive editions...

Page 3: ...bol and the course of action required will follow the symbol e g Bearings Pitting scratches Replace To assist you in finding your way through this manual the section title and major heading is given at the top of every page MODEL INDICATION Multiple models are referred to in this manual and their model indications are noted as fol lows ILLUSTRATIONS The illustrations within this service manual rep...

Page 4: ...UR SAFETY IS INVOLVED WARNING Failure to follow WARNING instructions could result in severe injury or death to the machine operator a bystander or a person inspecting or repairing the outboard motor CAUTION A CAUTION indicates special precautions that must be taken to avoid damage to the out board motor NOTE A NOTE provides key information to make procedures easier or clearer ...

Page 5: ... to refer to the job instruction charts at the same time as the exploded views These charts list the sequence that the procedures should be carried out in as well as providing explanations on part names quantities dimensions and important points relat ing to each relevant task 5 In addition to tightening torques the dimensions of the bolts and screws are also men tioned Example Bolt and screw size...

Page 6: ...ly Yamaha 2 stroke motor oil 17 Apply water resistant grease Yamaha grease A Yamaha marine grease 18 Apply water resistant grease Yamaha grease C Yamaha marine grease 19 Apply water resistant grease Yamaha grease D Yamaha marine grease 20 Apply molybdenum disulfide grease Symbols to in an exploded dia gram indicate the grade of the sealing or locking agent and the location of the appli cation poin...

Page 7: ... 9 CONTENTS GEN INFO SPEC CHK ADJ FUEL POWR LOWR BRKT ELEC TRBL ANLS GENERAL INFORMATION SPECIFICATIONS PERIODIC CHECK AND ADJUSTMENT FUEL SYSTEM RECOIL STARTER LOWER UNIT BRACKET UNIT ELECTRICAL SYSTEM TROUBLE ANALYSIS ...

Page 8: ......

Page 9: ... 1 2 FIRE PREVENTION 1 2 VENTILATION 1 2 SELF PROTECTION 1 2 OILS GREASES AND SEALING FLUIDS 1 2 GOOD WORKING PRACTICES 1 3 DISASSEMBLY AND ASSEMBLY 1 4 SPECIAL TOOLS 1 5 MEASURING 1 5 REMOVING AND INSTALLING 1 7 FEATURES AND BENEFITS 1 9 POWER UNIT 1 9 IGNITION SYSTEM 1 10 COOLING SYSTEM 1 11 TILLER HANDLE 1 13 BRACKET AND BOTTOM COWLING 1 14 ...

Page 10: ...he outboard motor s serial number is stamped is bonded to the port clamp bracket The label is specially treated so that peeling it off causes cracks across the serial number 1 Model name 2 Approval model code 3 Transom height 4 Serial number STARTING SERIAL NUMBERS The starting serial number blocks are as fol lows Model name Approval model code Starting serial number Worldwide EK25BMH 62C S 100101...

Page 11: ...etroleum vapor is heavier than air and is deadly if inhaled in large quantities Engine exhaust gases are harmful to breathe When test running an engine indoors maintain good ventilation SELF PROTECTION Protect your eyes with suitable safety glasses or safety goggles when grinding or when doing any operation which may cause particles to fly off Protect hands and feet by wearing safety gloves or pro...

Page 12: ...soiled wiping rag in your pocket 4 Hands and any other part of the body which have been in contact with lubri cants or lubricant contaminated cloth ing should be thoroughly washed with hot water and soap as soon as practica ble 5 To protect the skin the application of a suitable barrier cream to the hands before working is recommended 6 A supply of clean lint free cloths should be available for wi...

Page 13: ...arts with compressed air when disassembling 2 Oil the contact surfaces of moving parts before assembly 3 After assembly check that moving parts operate normally 4 Install bearings with the manufacturer s markings on the side exposed to view and liberally oil the bearings 5 When installing oil seals apply a light coating of water resistant grease to the outside diameter ...

Page 14: ...N 90890 01252 2 Crank stand alignment P N 90890 03107 3 Pocket tester P N 90890 03112 4 Timing light P N 90890 03141 5 Compression Gauge P N 90890 03160 6 Peak voltage adaptor P N 90890 03172 7 Digital circuit tester P N 90890 03174 8 Ignition tester P N 90890 06754 9 Vacuum pressure pump gauge set P N 90890 06756 10 Digital tachometer P N 90890 06760 11 Leakage tester P N 90890 06762 12 Digital c...

Page 15: ...3006 P N 90890 03008 15 Inside micrometer P N 90890 03010 16 Thickness gauge P N 90890 03079 17 Shimming plate P N 90890 06701 18 Pinion height gauge P N 90890 06702 19 Magnet base P N 90890 06705 20 Backlash indicator P N 90890 06706 21 Magnet base plate P N 90890 07003 13 14 15 16 17 18 19 20 21 ...

Page 16: ... y P N 90890 06535 10 Stopper guide stand P N 90890 06538 11 Driver rod LL P N 90890 06605 12 Driver rod LS P N 90890 06606 13 Driver rod L3 P N 90890 06652 14 Driver rod SL P N 90890 06602 15 Driver rod SS P N 90890 06604 16 Bearing depth plate P N 90890 06603 17 Needle bearing attachment P N 90890 06608 P N 90890 06611 P N 90890 06615 18 Ball bearing attachment P N 90890 06633 19 Bearing inner r...

Page 17: ...N 90890 02366 27 Height ring 13 H57 P N 90890 02379 28 Pressure Plate P N 90890 02384 29 Press body P N 90890 02385 30 Plate A P N 90890 02386 31 Plate B P N 90890 02387 32 Pressure pin B P N 90890 02390 33 Bearing pressure B P N 90890 02392 34 Bearing pressure C P N 90890 02393 35 Support P N 90890 02394 36 Spacer B P N 90890 02396 37 Bushing 14 P N 90890 02419 21 22 23 24 25 26 27 28 29 30 31 32...

Page 18: ... EK25A with newly designed linkage to control both throttle opening and ignition timing mechanically and simultaneously Special attention was paid on the crankshaft bearings Collar is now added to the upper main journal of the crankshaft Roller bearing is applied for the center bearing The collar added on the upper main journal contributes to get and better serviceability Fig 2 Fig 1 ...

Page 19: ... and ignition coil Similar to the previous EK25A the engine has the mechanical ignition timing advance system that works by way of the linkage Superior fuel economy is attained by the modified ignition timing control arrangement Also the system restricts the ignition timing advance to prevent engine kickback when the shift is in neutral Fig 3 ...

Page 20: ... structure applied to the cooling system provides additional cooling capacity in the upper casing With additional cooling water passage indicated by water walls contained in the new upper casing contribute to the reduction of outer surface temperature Fig 4 ...

Page 21: ...FEATURES AND BENEFITS 1 12 E GEN INFO COOLING SYSTEM Fig 5 ...

Page 22: ...to wide open positions Also new steering handle parts were developed to assume the long use Inner diameter of the steering handle engagement area and both inner and outer diameters of steering bracket are increased Please note that if the new steering handle is installed on the previous models Steering handle 2 Steering bracket Collar and Washer must be replaced Fig 7 Fig 6 ...

Page 23: ...ATURES AND BENEFITS 1 14 E GEN INFO BRACKET AND BOTTOM COWLING The Bracket 1 is modified on the EK25B and newly designed rubber seal is added to provide better sealing ability for the bottom cowling Fig 8 ...

Page 24: ......

Page 25: ... CHAPTER 2 SPECIFICATIONS GENERAL SPECIFICATIONS 2 1 MAINTENANCE SPECIFICATIONS 2 3 POWER UNIT 2 3 LOWER UNIT 2 5 ELECTRICAL 2 6 DIMENSIONS 2 8 DIMENSIONS 2 9 TIGHTENING TORQUES 2 11 SPECIFIED TORQUES 2 11 GENERAL TORQUES 2 12 ...

Page 26: ...n 18 4 25 0 Full throttle operating range r min 4 500 5 500 Maximum fuel consumption L US gal Imp gal 5 500 r min 13 8 3 6 3 0 Gasoline Kerosene POWER UNIT Type 2 stroke Number of cylinders 2 Displacement cm3 cu in 496 30 3 Bore and stroke mm in 72 0 61 0 2 83 2 40 Compression ratio kPa kgf cm2 psi 1 5 3 0 05 0 8 2 5 7 0 06 0 8 Compression pressure kPa kgf cm2 psi 1 680 6 8 98 6 2 730 7 3 105 9 Mi...

Page 27: ...gular gasoline Mixing ratio 50 1 Engine oil type 2 stroke outboard engine oil Engine oil grade TC W3 Gear oil Hypoid gear oil Gear oil grade SAE 90 API GL 4 Gear oil capacity cm3 US oz Imp oz 320 10 8 11 3 BRACKET Tilt angle Degree 4 8 12 16 20 Tilt up angle Degree 76 Shallow water angle from transom Degree Tilt angle 20 Steering angle Degree 40 40 DRIVE UNIT Gear shift positions F N R Gear ratio ...

Page 28: ...n side D mm in 71 94 71 96 2 8323 2 8331 Measuring point H mm in 10 0 0 3937 Piston cylinder clearance mm in 0 060 0 065 0 0024 0 0026 Limit mm in 0 1 0 0039 Oversize piston diameter 1st mm in 72 25 2 8445 2nd mm in 72 50 2 8543 Pin boss inside diameter mm in 19 904 19 915 0 7836 0 7841 PISTON PINS Outside diameter mm in 19 895 19 900 0 7833 0 7835 PISTON RING 1st Type Keystone B mm in 2 0 0 079 T...

Page 29: ... in 0 03 0 0012 Side clearance E mm in 0 2 0 7 0 0079 0 0276 Maximum axial play F mm in 2 0 0 079 CONNECTING ROD Small end diameter mm in 23 904 23 917 0 941 0 942 CARBURETOR Kerosene carburetor Gasoline carburetor Main jet M J 155 Main air jet M A J φmm in 1 3 0 051 Main nozzle M N φmm in 2 8 0 110 Pilot jet P J 50 48 Pilot air jet P A J mm in 0 92 0 036 0 90 0 035 Pilot screw P S turns out 1 2 2...

Page 30: ...lift mm in 3 0 12 Item Unit Model Worldwide EK25BMH Item Unit Model Worldwide EK25BMH GEAR BACKLASH Pinion forward gear mm in 0 31 0 72 0 012 0 028 Pinion reverse gear mm in 0 93 1 65 0 037 0 065 Pinion gear shims mm 0 7 1 0 1 1 1 2 1 3 1 4 1 5 1 6 Forward gear shims mm 1 0 1 1 1 2 1 3 1 4 Reverse gear shims mm 1 0 1 1 1 2 1 3 PROPELLER Material Aluminium No of blades diameter pitch in 3 9 7 8 11 ...

Page 31: ...istance Br L Ω 342 418 Charge coil output peak voltage Br L cranking 1 1 V 146 cranking 2 1 V 146 1 500 r min V 150 3 500 r min V 150 Pulser coil resistance W R B W B B Ω 311 381 Pulser coil output peak voltage W R B W B B cranking 1 1 V 6 8 cranking 2 1 V 6 7 1 500 r min V 16 0 3 500 r min V 26 0 CDI unit resistance Ω Refer to the CDI UNIT on page 8 10 CDI unit output peak voltage B O B B W B cra...

Page 32: ...NG SYSTEM Lighting coil resistance G G Ω 0 31 0 37 Lighting coil output peak voltage G G cranking 1 1 V 4 6 cranking 2 1 V 1 500 r min V 3 500 r min V 1 500 r min Open circuit V 14 7 3 500 r min Open circuit V 30 0 1 Cranking 1 Open circuit Cranking 2 Related parts are connected ...

Page 33: ...MAINTENANCE SPECIFICATIONS SPEC 2 8 E DIMENSIONS ...

Page 34: ...95 7 68 L10 mm in 74 2 2 92 H1 S mm in 707 27 83 L mm in 834 32 83 Y mm in 881 34 68 H2 mm in 439 17 28 H3 mm in 144 5 67 H4 S mm in 423 16 65 L mm in 550 21 65 Y mm in 597 23 50 H5 mm in 466 18 35 H6 S mm in 621 24 45 L mm in 701 27 60 Y mm in 730 28 74 H7 mm in 118 4 65 H8 mm in 30 1 18 H9 mm in 596 23 46 H10 mm in 40 3 1 59 W1 mm in 166 6 54 W2 mm in 233 9 17 W3 mm in 148 5 83 W4 mm in 192 7 56...

Page 35: ...ATIONS SPEC 2 10 E Symbol Unit Model Worldwide EK25BMH B1 mm in 89 3 50 B2 mm in 140 5 51 B3 mm in 112 5 4 43 B4 mm in 96 5 3 80 B5 mm in 122 5 4 82 B6 mm in 176 6 93 B11 mm in 85 3 35 B12 mm in 51 2 01 D1 φmm in 8 5 0 33 ...

Page 36: ...ounting 1st Bolt M6 15 4 0 4 3 0 2nd 8 0 8 5 9 Crankcase mounting 1st Bolt M8 10 15 1 5 11 2nd 30 3 0 22 LOWER UNIT Propeller Nut 1 35 3 5 26 Lower unit mounting Bolt M10 6 37 3 7 27 Nut M10 6 37 3 7 27 Propeller shaft housing Bolt M6 2 11 1 1 8 1 Pinion gear nut Nut M8 1 50 5 0 37 Water inlet Bolt M5 2 5 0 5 3 7 BRACKET Shift actuator mounting Bolt M6 4 11 1 1 8 1 Nut M10 1 17 1 7 13 Shift lever ...

Page 37: ... of this manual To avoid warpage tighten multi fastener assemblies in a crisscross fashion and progressive stages until the specified tightening torque is reached Unless other wise specified tightening torque specifica tions require clean dry threads Components should be at room tempera ture Nut A Bolt B General torque specifications N m kgf m ft lb 8 mm M5 5 0 5 3 7 10 mm M6 8 0 8 5 9 12 mm M8 18...

Page 38: ......

Page 39: ...E IGNITION TIMING 3 4 ADJUSTING THE ENGINE IDLE SPEED 3 15 ADJUSTING THE START IN GEAR PROTECTION DEVICE 3 17 POWER UNIT 3 18 MEASURING THE COMPRESSION PRESSURE 3 18 COOLING SYSTEM 3 19 CHECKING THE COOLING WATER DISCHARGE 3 19 LOWER UNIT 3 19 CHECKING THE GEAR OIL LEVEL 3 19 CHANGING AND CHECKING THE GEAR OIL 3 19 CHECKING THE LOWER UNIT FOR AIR LEAKS 3 20 GENERAL 3 21 CHECKING THE ANODE 3 21 CHE...

Page 40: ... with clean water after each use Item Remarks Initial Every Refer page 10 hours 50 hours 3 months 100 hours 6 months 200hours 1 year FUEL SYSTEM Fuel filter Clean 3 3 Fuel system Check 3 2 Fuel tank Clean POWER UNIT Carburetor setting Check 3 15 Adjust 3 15 Cooling water passage Clean Exhaust leakage Check Water leakage Check CONTROL SYSTEM Ignition timing Check 3 4 Adjust 3 4 Idle speed Check 3 1...

Page 41: ...eck Top cowling Cracks damage Replace Hook Bent Correct Rivet Damage Repair Rubber of trim Peel tear Repair NOTE Hooks and latches are unadjustable FUEL SYSTEM CHECKING THE FUEL LINE Check Fuel hose Cracks damage leak Replace Refer to FUEL JOINT FUEL FILTER AND FUEL PUMP on page 4 1 ...

Page 42: ...Cracks damage leak Replace O ring Cracks damage Replace CHECKING THE FUEL PUMP Check Fuel pump Cracks damage leak Repair replace Refer to DISASSEMBLING THE FUEL PUMP on page 4 4 NOTE Observe pump with naked eyes CHECKING THE FUEL JOINT Check Fuel joint Cracks damage leak Replace Seal Cracks damage Replace 1 2 3 1 2 ...

Page 43: ...ition timing Out of specification Adjust Checking steps 1 Install the timing light onto the spark plug lead of cylinder 1 2 Install the digital tachometer onto the spark plug lead of cylinder 1 3 Press the position key C on the digital tachometer 4 Start the engine and allow it to warm up for a few minutes Test propeller 90890 01629 Ignition timing at idle ATDC 2 2 Ignition timing at full advance ...

Page 44: ...close position 9 Check the ignition timing by pointing the timing light at the timing indicater on the starter case NOTE Ignition timing adjustment is not required if the timing indicator reading falls within the specification If the reading is out of specification adjust the timing by the following pro cedure Full throttle operating range 5 350 100 r min Ignition timing at full advance BTDC 22 2 ...

Page 45: ...ull open posi tion 3 Slowly turn the flywheel clockwise to align the full advanced timing mark with the specified position on the tim ing indicator 4 Turn the magnet base until the tim ing mark stamped on the port side comes in line with the ignition mark on the rotor 5 Check that the magnet base stopper is in contact with the stopper on the engine body full open end stopper 5 4 Ignition timing at...

Page 46: ...control link Accelerator cam Carburetor control link Adjustment steps 1 Set the shift lever in forward posi tion 2 Move the throttle to full open posi tion 3 Make sure that the magnet base stopper is in contact with the stopper on the engine body full open end stopper 4 Check to see that the full open marking C on the accelerator cam aligns with the center of the cam roller 6 4 3 6 1 2 3 4 ...

Page 47: ...at the throttle is full open the full open stopper is pushed against the stopper and lock the screw NOTE After adjustment open and close the throt tle repeatedly for several times to reassure that the full open position of the accelerator cam and the positioning of the carburetor control link stopper are correct 4 Adjustment with full closed throttle Accelerator cam Carburetor control link Adjustm...

Page 48: ...h the throttle stop screw move the plate cam to the left so that the lever comes to contact with the throttle stop screw NOTE When shifting the plate cam slightly do not shift it more than 2 mm 0 079 in to the left from the point at which the marking line of the full open mark C aligns with the centerline of the roller cam at full throttle After adjustment open and close the throttle for several t...

Page 49: ... contact with the stopper on the engine body full open end stopper 4 If the stoppers come in contact before the throttle is fully open loosen the lock nut on the throttle opening cable turn in the adjusting nut until the cerrect positioning is attained and then secure it by the lock nut 5 If the stoppers do not come in contact at full open throttle then turn out the adjusting nut on the throttle o...

Page 50: ...er full open throttle is completed move the throttle to full close position 8 Make sure that the magnet base stop per is in contact with the stopper on the engine body full close end stopper 9 Move the throttle to full open posi tion 10 In this condition make sure that the full open stopper is in contact with the stopper NOTE If they are not in contact adjust the carbu retor control link Refer to ...

Page 51: ...tor NOTE After adjustment open and close the throttle for several times for reassur ance If they are not in contact adjust the car buretor control link Refer to Adjusting the carburetor control link on page 3 7 6 Adjusting the throttle control lever Throttle control lever Adjustment steps 1 Set the shift lever at the forward position 2 Move the throttle to full open posi tion 2 1 2 ...

Page 52: ... adjustment open and close the throt tle repeatedly for several times to reassure the correct positioning 6 Check that the magnet base stopper is in contact with the stopper on the engine body full open end stopper NOTE If they are not in contact perform the adjustment with full open throttle Refer to Adjustment with full open throt tle on page 3 6 7 In this condition make sure that the full open ...

Page 53: ...d Engine idle speed Adjustment steps 1 Adjust the pilot screw 2 Adjust the idling stop screw Refer to ADJUSTING THE ENGINE IDLE SPEED on page 3 15 Pilot screw turn out Gasoline carburetor 1 1 2 1 2 Kerosene carburetor 1 2 2 1 2 1 2 Engine idle speed 1 300 50 r min ...

Page 54: ...e engine and allow it to warm up for a few minutes 2 Install the digital tachometer onto the spark plug lead of cylinder 1 3 Press the position key C on the digi tal tachometer 2 Adjust Carburetor pilot screw CAUTION Do not adjust the carburetor when it is operating properly Excessive adjustment may cause the engine poor performance Adjustment steps 1 Turn in the pilot screw Gasoline Kerosene unti...

Page 55: ...spec ified engine idle speed is obtained 2 Check the engine idling stability by opening and closing the throttle for several times If engine idling is unsta ble adjust the pilot screw NOTE After adjustment open and close the throttle for several times and keep it idling for at least 15 seconds Check if engine idle speed is stable Direction Engine idle speed i i i in n n nc c c cr r r re e e ea a a...

Page 56: ...pe cannot be pulled out 3 If the starter rope can be pulled out perform the adjustment 2 Adjust Adjustment steps 1 Set the shift lever in neutral position 2 Turn in or out the adjusting nut on the starter stop wire so that the starter stopper end is aligned with the hole on the starter case NOTE Check again that the starter rope can not be pulled out when the shift is engaged Check again that the ...

Page 57: ...vent any dirt from falling into the cylinder that is being checked 2 Install the compression gauge into the spark plug hole 3 Fully open the throttle 4 Fully open the choke Make the choke valve ineffective 5 Crank the engine by means of recoil starter MH model or starter motor W WC and WH models until the com pression gauge gives stable reading 6 Remove the compression gauge 7 Install the spark pl...

Page 58: ...ater flows from the pilot water outlet LOWER UNIT CHECKING THE GEAR OIL LEVEL Check Gear oil level Level is low Add gear oil to the proper level CHANGING AND CHECKING THE GEAR OIL 1 Check Gear oil Milky oil Replace the oil seal Slug oil Check the oil gears bear ings and clutch dog Checking steps 1 Tilt up the outboard slightly 2 Place a container under the gear oil drain screw 3 Remove the gear oi...

Page 59: ...NG THE LOWER UNIT FOR AIR LEAKS Check Lower unit holding pressure Pressure drops Check the seal and components Checking steps CAUTION Do not overpressurize the lower unit Excessive pressure may damage the oil seals 1 Remove the gear oil level check screw 2 Install the pressure tester into the check hole 3 Apply the specified pressure 4 The lower unit should hold the speci fied pressure for 10 seco...

Page 60: ...GENERAL CHK ADJ 3 21 E GENERAL CHECKING THE ANODE Check Anodes Scales Clean Oil grease Clean Excessive wear Replace CAUTION Do not oil grease or paint the anode or it will not operate properly ...

Page 61: ...ug cleaner or wire brush 3 Check Spark plug type Incorrect Replace 4 Measure Spark plug gap Out of specification Replace Color guide Medium to light tan color Normal Whitish color Lean fuel mixture Plugged jet s Wrong setting Blackish color Rich mixture Excessive oil usage Defective ignition system Defective spark plug Standard spark plug NGK B7HS 10 Spark plug gap 0 9 1 0 mm 0 035 0 039 in 1 2 1 ...

Page 62: ...ood estimate of the correct tightening torque is to finger tighten the spark plug and then tighten it another 1 4 to 1 2 of a turn CHECKING THE PROPELLER Check Propeller Spline Wear cracks damage Replace CHECKING BOLTS AND NUTS Check Power unit mount bolt Flywheel nut Loose bolts nuts Tighten to the specified torque T R Spark plug 25 N m 2 5kgf m 18 ft lb T R Power unit mount bolt 1st 11 N m 1 1 k...

Page 63: ...E Using a grease gun fill in the grease until it comes out of the bushing NOTE Use a grease gun NOTE Using a grease gun fill in the grease until it comes out of the bushing NOTE Using a grease gun fill in the grease until it comes out of the bushing NOTE Use a grease gun ...

Page 64: ...5 E NOTE Use a grease gun NOTE Grease the area where shift rod shift con nector and the nut are fastened NOTE Grease the sliding face of the choke knob NOTE Grease the inner cable and the lock nut 2 Apply Yamaha grease D ...

Page 65: ...G THE FUEL JOINT 4 3 CHECKING THE FUEL FILTER 4 3 ASSEMBLING THE FUEL FILTER 4 3 FUEL PUMP 4 4 DISASSEMBLING THE FUEL PUMP 4 4 CHECKING THE FUEL PUMP 4 6 ASSEMBLING THE FUEL PUMP 4 7 CARBURETOR 4 9 REMOVING THE CARBURETOR 4 9 DISASSEMBLING THE CARBURETOR 4 10 CHECKING THE CARBURETOR 4 16 ASSEMBLING THE CARBURETOR 4 17 INSTALLING THE CARBURETOR 4 20 ...

Page 66: ...p 2 2 Fuel hose fuel pump to carburetor 1 Gasoline 3 Clip 2 4 Fuel hose fuel pump to carburetor 1 Kerosene 5 Clip 2 6 Fuel hose fuel filter to fuel pump 1 Gasoline 7 Clip 2 8 Fuel hose fuel filter to fuel pump 1 Kerosene 9 Clip 2 10 Fuel hose fuel joint to fuel filter 1 Gasoline 11 Clip 2 12 Fuel hose fuel joint to fuel filter 1 Kerosene 13 Bolt 2 Continued on next page ...

Page 67: ...D FUEL PUMP 4 2 E FUEL Step Job Parts Q ty Remarks 14 Fuel pump 1 15 Gasket 1 Not reusable 16 Nut 2 17 Fuel filter 1 Gasoline 18 Fuel filter 1 Kerosene 19 Bolt 1 20 Bolt 1 21 Filter bracket 1 22 Bolt 1 23 Fuel joint 1 24 Seal 1 ...

Page 68: ...ssure pump gauge 2 Apply the specified pressure CHECKING THE FUEL FILTER Check Filter cap Cracks damage Replace Filter element Cracks damage leak Replace O ring Cracks damage Replace Cup Foreign matter Clean ASSEMBLING THE FUEL FILTER 1 Install filter element to cap 2 Install O ring to filter cup 3 Assemble cap and filter cup NOTE Start the engine and confirm the proper function Vacuum pressure pu...

Page 69: ...UEL PUMP Step Job Part Q ty Remarks 1 Screw with washer 3 2 Body 1 3 Diaphragm 1 4 Gasket 1 Not reusable 5 Body 1 6 Diaphragm gasket 2 Not reusable 7 Diaphragm 1 8 Body 1 9 Screw 2 10 Seat valve 2 11 Nut 2 12 Screw 3 13 Washer 3 Continued on next page ...

Page 70: ...FUEL PUMP FUEL 4 5 E Step Job Part Q ty Remarks 14 Body 1 15 Diaphragm 1 16 Diaphragm gasket 1 ...

Page 71: ...o not overpressurize the fuel pump Exces sive pressure may cause air to leak out 1 Install the Vacuum pressure pump gauge set onto the fuel pump as shown 2 Apply the specified pressure with the Vacuam pressure pump gauge set NOTE Make sure no air comes out of the opposite side of the fuel pump Start the engine and confirm the proper function Vacuum pressure pump gauge set 90890 06756 Fuel pump pre...

Page 72: ...re assembly Assembly steps 1 Assemble Body and seat valve 2 Insert the diaphragm between the dia phragm gaskets and set them on Body 3 Set Body on the diaphragm gasket 4 Fit diaphragm and gasket on Body 5 Assemble Body as has been fitted in 4 to Body 2 1 3 1 3 1 2 1 3 3 1 ...

Page 73: ...FUEL PUMP 4 8 E FUEL 6 Assemble body diaphragm and diaphragm gasket in this order 7 Assemble body and body and fasten them with the screw 4 1 4 4 4 1 ...

Page 74: ...CARBURETOR FUEL 4 9 E CARBURETOR REMOVING THE CARBURETOR Step Job Part Q ty Remarks 1 Rod 1 2 Bolt 2 3 Intake silencer 1 4 O ring 1 Not reusable 5 Nut 2 6 Carburetor 1 7 Gasket 1 Not reusable ...

Page 75: ... 1 Drain screw 1 2 Drain gasket 1 Not reusable 3 Drain screw 1 4 Drain gasket 1 Not reusable 5 Drain screw 1 6 Packing 1 Not reusable 7 Steel ball seat 1 8 Steel ball 1 9 Check valve spring 1 10 Check valve seat packing 1 11 Rod 1 12 Lever joint 2 13 Hose 1 Continued on next page ...

Page 76: ...emarks 14 Bolt 4 15 Bolt 3 16 Float chamber 1 17 Float chamber packing 1 18 Chamber packing 1 19 Starter jet 1 20 Check valve 1 21 O ring 1 Not reusable 22 Pump spring 1 23 Pump plunger 1 24 Float 1 25 Pilot jet 1 26 Pin 1 Continued on next page ...

Page 77: ... Q ty Remarks 27 Float arm 1 28 Needle valve 1 29 Chamber cover 1 30 Set screw 1 31 Washer 1 32 Pump lever 1 33 Coller 1 34 Pin 1 35 Float 1 36 Needle valve 1 37 Valve seat 1 38 Packing 1 Not reusable 39 Main jet 1 Continued on next page ...

Page 78: ...40 Main nozzle 1 41 Steel ball seat 1 42 Steel ball 1 43 Check valve spring 1 44 Check valve seat packing 1 45 Screw 1 46 Rod 1 47 Lever joint 1 48 Nut 1 49 Spring washer 1 50 Coller 1 51 Accel arm 1 52 Cotter pin 1 Not reusable Continued on next page ...

Page 79: ...ty Remarks 53 Washer 1 54 Accel roller 1 55 Accel link shaft 1 56 Coller 1 57 Pilot screw 1 Kerosene 58 Spring 1 59 Pilot screw 1 Gasoline 60 Spring 1 61 Idling stop screw 1 62 Spring 1 63 Bolt 3 64 Plate 1 65 Damper 1 Continued on next page ...

Page 80: ...Part Q ty Remarks 66 Hose 1 67 Hose 1 68 Cover plate 1 69 Cover plate packing 1 70 Plunger spring 1 71 Guide screw 1 72 Starter lever 1 73 Starter plunger 1 74 Pilot jet 1 75 Drain screw 1 76 O ring 1 Not reusable 77 Carburetor body 1 ...

Page 81: ...ear Replace Pilot screw Bent wear Replace Main jet Contamination Clean Pilot jet Contamination Clean Main nozzle Contamination Clean Float Cracks damage Replace Pump plunger Cracks damage Replace Fuel passage Clog Clean Air passage Clog Clean NOTE Use a suitable cleaning solvent and blow out clogged passages with compressed air WARNING Protect your eyes with suitable safety spec tacles or safety g...

Page 82: ...4 17 E ASSEMBLING THE CARBURETOR 1 Install Main nozzle Main jet Valve seat Needle valve Float Float pin NOTE When installing the float into the carbure tor place the needle valve into the needle valve seat 1 2 3 4 5 6 ...

Page 83: ... the float flange opposite to its pivoted side Float height which is out of specifica tion cannot be adjust Replace the float with a new one 3 Install Float chamber packing Float chamber 4 Install Accel arm Accel link shaft 5 Install Pilot screw Gasoline Pilot screw Kerosene CAUTION Do not cause damage to the tip of the pilot screw by over tightening it Float height 18 0 mm 0 709 in a 1 2 1 2 1 2 ...

Page 84: ... Cover plate Damper 7 Install Float arm Pin Needle valve 8 Measure Float arm height Out of specification Adjust NOTE Adjust the heights of both float arms so that they are on the same level Float arm height 3 0 mm 0 118 in 1 2 1 2 3 a ...

Page 85: ...the projection of choke lever into the choke knob hole 2 Adjust Pilot screw Adjusting steps 1 Turn in all of the pilot screw until they are lightly seated 2 Turn out the pilot screws to specified number of turns 3 Make sure that the idle speed is stable when the throttle is opened and closed for several times Pilot screw turn out Gasoline carburetor 1 1 2 1 2 Kerosene carburetor 1 2 2 1 2 1 2 1 2 ...

Page 86: ...peed Out of specification adjust Measuring steps 1 Start the engine and allow it to warm up for a few minutes 2 Install the Digital tachometer onto the spark plug lead of cylinder 1 Engine idle speed 1 300 50 r min Digital Tachometer 90890 06760 1 ...

Page 87: ......

Page 88: ... AND REED VALVES 5 17 REMOVING THE INTAKE MANIFOLD AND REED VALVES 5 17 CHECKING THE REED VALVES 5 18 INSTALLING THE INTAKE MANIFOLD 5 18 CYLINDER HEAD 5 19 REMOVING THE CYLINDER HEAD 5 19 CHECKING THE CYLINDER HEAD 5 20 CHECKING THE THERMOSTAT 5 21 INSTALLING THE CYLINDER HEAD AND CYLINDER HEAD COVER 5 22 INSTALLING THE THERMOSTAT 5 22 EXHAUST COVER 5 23 REMOVING THE EXHAUST COVER 5 23 CHECKING T...

Page 89: ...E PISOTN RINGS 5 33 CHECKING THE CRANKSHAFT 5 34 INSTALLING THE PISTON AND PISTON RINGS 5 37 INSTALLING THE CRANKSHAFT AND PISTON 5 37 CHECKING THE ANODE 5 38 CRANK SHAFT 5 39 DISASSEMBLING THE CRANKSHAFT 5 39 REMOVING THE CRANKSHAFT BEARING 5 41 ASSEMBLING THE CRANKSHAFT 5 44 INSTALLING CRANKSHAFT BEARING 5 50 CHECKING THE CRANKSHAFT 5 51 ...

Page 90: ...RECOIL STARTER 5 1 E POWR 5 RECOIL STARTER REMOVIING THE RECOIL STARTER Step Job Parts Q ty Remarks 1 Starter stop wire 1 2 Bolt with washer 3 3 Nut 2 4 Recoil starter 1 5 Collar 2 ...

Page 91: ...p Job Parts Q ty Remarks 1 Starter stop wire 1 2 Starter stop plunger 1 3 Spring 1 4 Cover 1 5 Starter handle grip 1 6 Damper 1 7 Bolt with washer 2 8 Rope guide 1 9 Nut 1 10 Center bolt 1 11 Thrust washer 1 12 Friction plate 1 13 Collar 1 1 Continued on next page ...

Page 92: ... STARTER 5 3 E POWR Step Job Parts Q ty Remarks 14 Friction spring 1 15 Drive pawl 1 16 Return spring 1 17 Bushing 1 18 Sheave drum 1 19 Starter rope 1 20 Spiral spring 1 21 Thrust washer 1 22 Starter case 1 ...

Page 93: ... drum from the starter case hold down the spiral spring with screwdriver inserted into the hole in the sheave drum so that the spiral spring will not spring out WARNING When removing the sheave drum be sure to set the spring free and remove the sheave retainer bolt Otherwise the spiral spring may jump out endangering other person 3 Remove Spiral spring NOTE Hold the spring with one hand and unfold...

Page 94: ...ring use care not to injure your hand It is advisable to wear gloves 4 Check Bushing Cracks damage wear Replace 5 Check Spiral spring Bent broken damage Replace 6 Check Starter rope Damage frays wear Replace 7 Check Sheave drum Starter case Cracks damage wear Replace 1 1 1 1 2 ...

Page 95: ... end onto the spring pin first place into the starter case and then remove the steel hoop 1 Install Starter case Thrust washer Spiral spring NOTE Hook the outer end of the spiral spring onto the spring pin attached to the starter case and put the spring into the starter case by winding it counterclockwise WARNING When removing or installing the spiral spring use care not to injure your hand It is ...

Page 96: ...ed starter rope it could cause injury 3 Install Bushing NOTE Mount the bushing on the starter case shaft 4 Install Sheave drum NOTE While turning the sheave drum fit the sheave drum shaft slot into the spiral spring hook and then place the sheave drum shaft into the starter case boss 5 Install Return spring Drive pawl NOTE Hook the end of the return spring onto the drive pawl and check to see that...

Page 97: ...ate Collar 1 Friction spring 7 Install Friction plate with friction spring etc Center bolt Nut 8 Install Starter rope Damper Starter handle grip Cover 1 2 3 T R Center bolt 15 N m 1 5 kgf m 11 ft lb Nut 10 N m 1 0 kgf m 7 4 ft lb 1 2 3 1 2 3 1 2 3 4 ...

Page 98: ...r han dle grip and make a knot in the end of the rope as shown After assembling wind the rope 3 turns counterclockwise around the sheave drum to contract the spring By pulling out the rope check the oper ation of the starter INSTALLING THE RECOIL STARTER Install Recoil starter Starter stop wire Refer to the ADJUSTING THE START IN GEAR PROTECTION DEVICE on page 3 17 1 2 ...

Page 99: ...FLYWHEEL MAGNET POWR 5 10 E FLYWHEEL MAGNET REMOVIING THE FLYWHEEL MAGNET Step Job Part Q ty Remarks 1 Bolt 3 2 Starter pulley 1 3 Nut 1 4 Washer 1 5 Flywheel magnet 1 6 Woodruf key 1 ...

Page 100: ...of the arrows Apply the load until the flywheel mag net comes off the tapered portion of the crankshaft CAUTION To prevent damage to the engine or tools screw in the flywheel puller set bolts evenly and completely so that the puller plate is parallel to the flywheel magnet INSTALLING THE FLYWHEEL MAGNET Install Flywheel magnet NOTE The major load should be applied in the direction of the arrows If...

Page 101: ... UNIT DISCONNECTING THE LEADS AND STAYS Step Job Part Q ty Remarks 1 Bolt 4 2 Washer 2 3 Bolt 1 4 Electrical unit 1 5 Bolt 1 6 Earth lead 1 7 Bolt 2 8 Bolt 1 9 Stay 1 10 Bolt 2 11 Stay 1 12 Bolt 1 13 Stay 1 Continued on next page ...

Page 102: ...POWER UNIT 5 13 E POWR Step Job Part Q ty Remarks 14 Bolt 2 15 CDI unit 1 16 Bolt 2 17 Ignition coil 2 18 Bracket 1 19 Pipe 4 20 Damper 4 21 Grommet 1 ...

Page 103: ...E REMOVING THE POWER UNIT Step Job Part Q ty Remarks 1 Cotter pin 1 Not reusable 2 Washer 1 3 Wavewasher 1 4 Throttle cable 1 1 5 Throttle cable 2 1 6 Bolt with washer 6 7 Power unit 1 8 Dowel pin 2 9 Gasket 1 Not reusable ...

Page 104: ... MAGNET BASE AND MAGNET CONTROL LEVER Step Job Part Q ty Remarks 1 Clamp 1 2 Joint link 1 3 Bolt 4 4 Magnet base 1 5 Screw 2 6 Change coil 1 7 Screw 2 8 Lighting coil 1 9 Screw 4 10 Pulser coil 2 11 Screw 4 12 Magnet base retainer 2 1 13 Magnet base retainer 1 1 Continued on next page ...

Page 105: ...R 5 16 E Step Job Part Q ty Remarks 14 Magnet base friction plate 1 15 Joint link 1 16 Bolt with washer 1 17 Collar 1 18 Magneto control lever 1 19 Bolt with washer 1 20 Throttle cable stay 1 21 Bolt with washer 1 22 Collar 1 23 Arm 1 ...

Page 106: ...REED VALVES REMOVING THE INTAKE MANIFOLD AND REED VALVES Step Job Part Q ty Remarks 1 Bolt with washer 1 2 Bolt with washer 2 3 Clamp Fuel hose 1 4 Bolt with washer 6 5 Intake manifold 1 6 Intake manifold gasket 1 Not reusable 7 Reed valve 1 8 Gasket 1 Not reusable ...

Page 107: ...cation Replace INSTALLING THE INTAKE MANIFOLD Install Intake manifold NOTE Tighten the intake manifold mounting bolts in two steps of torque Apply LOCTITE No 572 on the bolts Valve bending limit 0 2 mm 0 008 in Valve stopper height Standard 3 46 3 50 mm 0 136 0 138 in for Sri Lanka 4 20 4 60 mm 0 165 0 181 in T R Intake manifold mounting bolt 1st 4 N m 0 4 kgf m 3 0 ft lb 2nd 8 N m 0 8 kgf m 5 9 f...

Page 108: ...marks 1 Spark plug 2 2 Hose 1 3 Bolt with washer 3 4 Thermostat cover 1 5 Gasket 1 Not reusable 6 Plain washer 1 7 Thermostat 1 8 Bolt with washer 11 9 Bolt with washer 2 10 Cylinder head cover 1 11 Head cover gasket 1 Not reusable 12 Cylinder head 1 13 Cylinder head gasket 1 Not reusable ...

Page 109: ...r head and cylinder head cover 2 Measure Cylinder head warpage use a straightedge and thickness gauge Out of specification Resurface replace Resurfacing steps 1 Place a 400 600 grit wet sandpaper on the surface plate 2 Resurface the cylinder head by moving it in a figure eight motion along the sandpaper NOTE Rotate the cylinder head several times to ensure an even surface Warpage limit 0 1 mm 0 00...

Page 110: ...rmostat opens at the specified tem perature W W W Wa a a at t t te e e er r r r t t t te e e em m m mp p p pe e e er r r ra a a at t t tu u u ur r r re e e e V V V Va a a al l l lve ve ve ve li li li lif f f ft t t t B B B Be e e el l l lo o o ow w w w 48 48 48 48 52 52 52 52 C C C C 1 1 1 11 1 1 18 8 8 8 1 1 1 12 2 2 26 6 6 6 F F F F 0 0 0 0 mm mm mm mm 0 0 0 0 i i i in n n n A A A Ab b b bo o o ...

Page 111: ...assembled parts onto the crank case Apply LOCTITE No 572 on the bolts Tighten the cylinder head mounting bolts and nut in sequence and in two steps of torque INSTALLING THE THERMOSTAT Install Thermostat Plain washer Gasket Thermostat cover Bolt NOTE Always use the new gasket Tighten the bolts in sequence T R Cylinder head mounting bolts 1st 15 N m 1 5 kgf m 11 ft lb 2nd 30 N m 3 0 kgf m 22 ft lb T...

Page 112: ... 23 E POWR EXHAUST COVER REMOVING THE EXHAUST COVER Step Job Part Q ty Remarks 1 Bolt with washer 12 2 Bolt with washer 3 3 Exhaust outer cover 1 4 Gasket 1 Not reusable 5 Exhaust inner cover 1 6 Gasket 1 Not reusable ...

Page 113: ... Cracks damage Replace CAUTION Do not scratch the fitting surfaces of the cylinder and exhaust cover INSTALLING THE EXHAUST COVER Install Exhaust cover NOTE Apply LOCTITE No 572 on the bolts Tighten the exhaust cover mounting bolts in sequence and in two steps of torque T R Exhaust cover mounting bolts 1st 4 N m 0 4 kgf m 3 0 ft lb 2nd 8 N m 0 8 kgf m 5 9 ft lb ...

Page 114: ...CASE REMOVING THE CRANKCASE Step Job Part Q ty Remarks 1 Bolt with washer 8 2 Bolt with washer 2 3 Crankcase 1 4 Bolt with washer 1 5 Oil seal housing 1 6 O ring 1 Not reusable 7 Oil seal 1 Not reusable 8 Oil seal 2 Not reusable ...

Page 115: ...nkcase and cylinder body 2 Apply Gasket Maker onto the match ing surfaces of the cylinder body and the crankcase 3 Also apply Gasket Maker on the oil seal housing NOTE Do not allow any sealant to overflow from the matching surfaces 2 Install Oil seal housing NOTE Do not give any damage to the lip when installing the oil seal 1 2 3 3 Needle bearing attachment 90890 06608 Ball bearing attachment 908...

Page 116: ...3 Install Crankcase NOTE Apply LOCTITE No 572 on the bolts Tighten the crankcase mounting bolts in sequence and in two steps of torque T R Crankcase mounting bolts 1st 15 N m 1 5 kgf m 11 ft lb 2nd 30 N m 3 0 kgf m 22 ft lb ...

Page 117: ... CYLINDER BODY REMOVING THE CRANKSHAFT AND CYLINDER BODY 1 2 3 4 5 5 6 7 8 3 Step Job Part Q ty Remarks 1 Crankshaft 1 2 Cylinder body 1 3 Piston pin clip 4 4 Piston pin 2 5 Piston pin washer 4 6 Small end bearing 68 34 pins 1set 7 Piston ring 4 8 Piston 2 ...

Page 118: ...ntacting surfaces of the crankcase and cylinder head 2 Check Exhaust passage Cracks damage Replace Carbon deposits Clean use a round scraper CAUTION Do not scratch the contacting surfaces of the cylinder and exhaust cover 3 Measure Cylinder bore D use a cylinder gauge Out of specification Rebore replace NOTE Measure the cylinder bore diameter at three positions for both D1 and D2 Then aver age the...

Page 119: ...2 72 72 72 1 1 1 10 0 0 0 mm mm mm mm 2 2 2 2 8 8 8 8386 386 386 386 i i i in n n n T T T Ta a a ap p p pe e e er r r r li li li lim m m mi i i it t t t T T T T 0 0 0 0 0 0 0 08 8 8 8 mm mm mm mm 0 0 0 0 0 0 0 00 0 0 031 31 31 31 i i i in n n n O O O Ou u u ut t t t o o o of f f f r r r roun oun oun ound d d d li li li lim m m mi i i it t t t R R R R 0 0 0 0 0 0 0 05 5 5 5 mm mm mm mm 0 0 0 0 0 0 ...

Page 120: ...0890 03008 Measuring point H Piston diameter S S S St t t ta a a and nd nd nda a a ar r r rd d d d 10 0 mm 0 3937 in 71 94 71 96 mm 2 8323 2 8331 in O O O Ove ve ve ver r r r s s s si i i iz z z ze e e e p p p pi i i is s s st t t ton d on d on d on di i i ia a a am m m me e e et t t te e e er r r r 1 1 1 1 72 72 72 72 2 2 2 25 5 5 5 mm mm mm mm 2 2 2 2 84 84 84 844 4 4 45 5 5 5 i i i in n n n 2 2...

Page 121: ... 2 Measure Piston pin outside diameter use an outside micrometer Out of specification Replace 3 Measure Piston pin boss inside diameter use an inside micrometer Out of specification Replace Outside micrometer 90890 03006 Piston pin outside diameter 19 895 19 900 mm 0 7833 0 7835 in Inside micrometer 90890 03010 Piston pin boss inside diameter 19 904 19 915 mm 0 7836 0 7841 in ...

Page 122: ... THE PISOTN RINGS NOTE Before checking the piston rings be sure to check the cylinder body Piston rings should be replaced as a set per piston 1 Check Piston ring Broken damage Replace 2 Measure Piston ring end gap use a thickness gauge Out of specification Replace Piston ring end gap 0 20 0 35 mm 0 0079 0 0137 in Piston ring end gap limit 0 35 mm 0 014 in Measuring point H 15 mm 0 591 in a ...

Page 123: ...ring side clear ance the outside of the piston ring should be flush with the piston wall CHECKING THE CRANKSHAFT 1 Measure Crank width use the digital caliper Out of specification Repair replace Piston ring side clearance Top 0 03 0 05 mm 0 0012 0 0020 in 2nd 0 03 0 07 mm 0 0012 0 0028 in Crank width 56 90 56 95 mm 2 2401 2 2421 in Crank width 153 7 154 0 mm 6 0512 6 0630 in Crank width 39 9 40 1 ...

Page 124: ...easure Connecting rod side clearance Use a thickness gauge Out of specification Repair replace 4 Measure Axial play Out of specification Repair replace Crank stand alignment 90890 03107 Dial gauge set 90890 01252 Runout limit 0 03 mm 0 0012 in Connecting rod side clearance 0 2 0 7 mm 0 0079 0 0276 in Maximum axial play 2 0 mm 0 079 in d e f ...

Page 125: ...36 E 5 Check Crankshaft bearings Abnormal noise damage roughness Replace CAUTION Do not use compressed air to spin the bear ings dry This causes damage to the bearing surfaces NOTE Do not reuse the bearing always replace it with a new one ...

Page 126: ...roke motor oil on the pis ton ring and piston ring groove INSTALLING THE CRANKSHAFT AND PISTON 1 Install Small end bearing 2 Install Piston Installing steps 1 Assemble the washer and the piston to the crankshaft 2 Push out the small end bearing installer with piston pin 3 Install circlip CAUTION Install the piston with UP mark on the piston crown facing towards the flywheel side NOTE Apply Yamaha ...

Page 127: ...ston and their ring grooves Coat all the crankshaft bearings with the engine oil The crankshaft bearing locating pin should fit into the slit in the cylinder The UP mark on the piston crown should be on the flywheel side CHECKING THE ANODE Check Anode Wear Replace Corrosion Sand NOTE When it is reduced to the size of one third 1 3 replace it 1 3 2 3 1 1 1 2 3 1 ...

Page 128: ...RANKSHAFT Step Job Part Q ty Remarks 1 O ring 1 Not reusable 2 Oil seal 1 Not reusable 3 Bearing 1 4 Collar 1 5 Crank 1 1 6 Crank pin 2 7 Washer 4 8 Connecting rod 2 9 Bearing 2 10 Crank 2 1 11 Bearing 1 12 Labyrinth seal 1 13 Clip 1 Continued on next page ...

Page 129: ...CRANK SHAFT POWR 5 40 E Step Job Part Q ty Remarks 14 Crank 3 1 15 Crank 4 1 16 Bearing 1 17 Washer 1 ...

Page 130: ... always be replaced as a set Once removed do not reuse the collar Always replace it with a new one Lower bearing Remove Lower bearing NOTE By forcing the pressure pin B with a hydraulic press remove the bearing When forcing out the crank pin use care so that the crankshaft does not fall off CAUTION Apply pressure to the pressure pin B slowly Hold the pressure pin in line with the press screw spind...

Page 131: ...low the same procedure CAUTION Apply pressure to the pressure pin B slowly Hold the pressure pin B in line with the press screw spindle Crank 2 and crank 3 removal 1 Remove Crank 2 Crank 3 NOTE Place the pressure pin B on the crank 2 center shaft and force it out using a press When forcing out the crank pin use care so that the crank does not fall off 1 a b 1 Plate A 90890 02386 Pressure pin B 908...

Page 132: ... B slowly Hold the pressure pin B in line with the press screw spindle 2 Remove Labyrinth seal Clip 3 Remove Bearing Removing steps 1 Remove roller bearing outer race 2 Remove roller bearing inner race using hydraulic press OK 1 2 Bearing separator 90890 06534 a a 1 2 ...

Page 133: ...When reassembling the crankshaft wash all component parts in suitable cleaning solvent Always use new bearings and crank pins Fitting the crank pin to the crank 2 and crank 4 1 Install Spacer B to crank pin hole Crank 2 2 Install Crank pin new NOTE Insert the crank pin into the pin hole by tapping it with a copper hammer Apply Yamaha 2 stroke motor oil on the crank pin 4 5 Plate A 90890 02386 Pres...

Page 134: ...the crank pin is set squarely to the crank web Assembling cranks 1 and 2 3 and 4 1 Install special service tools Flange Body Bolt Washer Bushing 5 D25 Height ring 13 H57 NOTE Align the cut in the height ring with cut in the body Flange 90890 02351 Body 90890 02352 Bolt 90890 02353 Washer 90890 02354 Bushing 5 D25 90890 02359 Height ring 13 H57 90890 02379 4 4 6 1 2 3 4 a b 1 2 3 4 ...

Page 135: ...rod and washer 4 Install special service tools Pressure plate Bushing 14 for crank 1 or Bushing 12 for crank 3 5 Install Crank 1 or crank 3 on the bush ing 6 Install Crank 1 or crank 3 use pressure plate NOTE Align the crank pin hole with the crank pin fitted to crank 2 or crank 4 Apply Yamaha 2 stroke motor oil on the crank 1 or crank 3 9 c 8 2 3 1 Bushing 14 for crank 1 90890 02419 Bushing 12 D3...

Page 136: ... 2 stroke motor oil on the crank pin 8 Measure Crank width Use the digital caliper Out of specification Reassemble repress Measurements should be made at to NOTE If either distance is out of specification reassemble or repress the crankshaft a Press body 90890 02385 Digital caliper 90890 06704 Crank width 56 90 56 95 mm 2 2401 2 2421 in 4 a 1 5 a ...

Page 137: ... fit Roller bearing inner race NOTE Position the roller bearing with the stamped mark facing upward and press fit it until it contacts the crank 2 Apply Yamaha 2 stroke motor oil on the roller bearing CAUTION Be sure to press fit the roller bearing squarely onto crank 2 12 Install Roller bearing outer race 3 a Thickness gauge mm 90890 06054 Connecting rod side clearance 0 2 0 7 mm 0 0079 0 0276 in...

Page 138: ...l on the labyrinth seal 2 Install Plate B between crank 1 and crank 2 Crank 1 and crank 2 on the crank 3 CAUTION Align the match marks on crank 3 and 2 Apply Yamaha 2 stroke motor oil on the crank 3 and 2 3 Press fit Crank 2 and crank 3 apply a force of 7 ton Plate A 90890 02386 Plate B 90890 02387 Height ring 13 H57 90890 02379 Press body 90890 02385 1 2 3 1 2 3 1 a 1 2 ...

Page 139: ...k facing upward Apply Yamaha 2 stroke motor oil on the bearing Be sure to press fit the ball bearing squarely onto crank 4 Upper bearing for crank 1 1 Install Collar 2 Install Upper bearing to crank 1 Install the upper bearing with hands NOTE Apply Yamaha grease A water resistant grease on the collar and upper bearing a 1 2 Bearing pressure B 90890 02392 Bushing 5 D25 90890 02359 Bearing pressure ...

Page 140: ...12 in or more adjust the crankshaft so that the reading is less than 0 03 mm 0 0012 in Use a copper hammer as shown 2 Measure Axial play Out of specification Repair replace CHECKING THE CRANKSHAFT Refer to CHECKING THE CRANKSHAFT on page 5 34 Crank stand alignment 90890 03107 Digital gauge set 90890 01252 Runout limit 0 03 mm 0 0012 in Maximum axial play 2 0 mm 0 079 in 1 2 f ...

Page 141: ......

Page 142: ... SHAFT 6 9 REMOVING THE PROPELLER SHAFT HOUSING 6 10 DISASSEMBLING THE PROPELLER SHAFT HOUSING 6 10 CHECKING THE REVERSE GEAR 6 11 CHECKING THE BEARING 6 11 CHECKING THE PROPELLER SHAFT HOUSING 6 11 ASSEMBLING THE PROPELLER SHAFT HOUSING 6 12 CHECKING THE DOG CLUTCH 6 13 CHECKING THE PROPELLER SHAFT 6 13 CHECKING THE SHIFT PLUNGER 6 13 CHECKING THE SHIFT SPRING 6 13 DRIVE SHAFT 6 14 REMOVING THE D...

Page 143: ...THE NEEDLE BEARING 6 20 ASSEMBLING THE LOWER CASE 6 20 SHIMMING 6 21 SELECTING THE PINION SHIMS 6 22 SELECTING THE FORWARD GEAR SHIMS 6 24 SELECTING THE REVERSE GEAR SHIMS 6 26 BACKLASH 6 28 MEASURING THE FORWARD GEAR BACKLASH 6 28 MEASURING THE REVERSE GEAR BACKLASH 6 29 ...

Page 144: ...E LOWER UNIT Step Job Part Q ty Remarks 1 Cotter pin 1 Not reusable 2 Castle nut 1 3 Washer 1 4 Spacer 1 5 Propeller 1 6 Spacer 1 7 Nut 1 8 Shift connector 1 9 Bolt with washer 1 10 Trim tab 1 11 Bolt 1 12 Anode 1 13 Screw 2 Continued on next page ...

Page 145: ...14 Nut 2 15 Water inlet cover 1 1 16 Water inlet cover 2 1 17 Gear oil level check screw 1 18 Gasket 1 19 Gear oil drain screw 1 20 Gasket 1 21 Bolt 4 Transom S L 22 Nut 4 Transom Y 23 Lower unit 1 24 Pin 2 25 Extension 1 Transom Y 26 Pin 2 Transom Y ...

Page 146: ...Replace INSTALLING THE PROPELLER Install Propeller WARNING Do not hold the propeller with your hands when removing or installing it Be sure to remove the battery leads from the batter ies and the lanyard engine stop switch Put a block of wood between the cavitation plate and propeller to keep the propeller from turning NOTE If the groove in the propeller nut is not aligned with the cotter pin hole...

Page 147: ...Part Q ty Remarks 1 Bolt 4 2 Plate 1 Transom S L 3 Water tube 1 4 O ring 1 Not reusable 5 O ring 1 Not reusable 6 Water seal rubber 1 7 Water pump housing 1 8 Insert cartridge 1 9 O ring 1 Not reusable 10 Impeller 1 11 Impeller plate 1 12 Dowel pin 1 13 Woodruff key 1 ...

Page 148: ...k Woodruff key Damage wear Replace INSTALLING THE IMPELLER AND WATER PUMP HOUSING Install Impeller Insert cartridge Water pump housing NOTE When installing the insert cartridge align its projection with the hole in the water pump housing When installing the water pump hous ing turn the drive shaft clockwise Apply Yamaha grease A water resis tant grease on the impeller the insert cartridge and the ...

Page 149: ... ROD Step Job Part Q ty Remarks Impeller plate Refer to WATER PUMP on page 6 4 1 Bolt 2 2 Bracket 1 3 Plate 1 4 O ring 1 Not reusable 5 Oil seal housing 1 6 Lower casing packing 1 Not reusable 7 Dowel pin 1 8 Shift rod 1 9 Rubber seal 1 10 Oil seal 2 ...

Page 150: ...OUSING REMOVING THE PROPELLER SHAFT HOUSING Step Job Part Q ty Remarks Gear oil Refer to CHANGING AND CHECKING THE GEAR OIL on page 3 19 Shift rod assembly Refer to SHIFT ROD on page 6 6 1 Bolt 2 2 Propeller shaft housing 1 3 Washer 1 4 Propeller shaft 1 ...

Page 151: ...BLING THE PROPELLER SHAFT HOUSING As required Step Job Part Q ty Remarks 1 O ring 1 Not reusable 2 O ring 2 Not reusable 3 Reverse gear 1 4 Reverse gear shim 5 Ball bearing 1 6 Oil seal 2 7 Needle bearing 1 8 Propeller shaft housing 1 9 Washer 1 ...

Page 152: ...6 9 E PROPELLER SHAFT HOUSING LOWR DISASSEMBLING THE PROPELLER SHAFT Step Job Part Q ty Remarks 1 Shift plunger 1 2 Cross pin ring 1 3 Cross pin 1 4 Spring 1 5 Dog clutch 1 6 Propeller shaft 1 ...

Page 153: ...SSEMBLING THE PROPELLER SHAFT HOUSING 1 Remove Reverse gear 1 2 3 Bearing housing puller claw 90890 06546 Stopper guide plate 90890 06501 Center bolt 90890 06504 1 2 3 1 4 3 2 Bearing separator 90890 06534 Stopper guide plate 90890 06501 Stopper guide stand 90890 06538 Bearing puller ass y 90890 06535 1 2 3 4 ...

Page 154: ...SE GEAR Check Teeth Dogs Damage wear Replace CHECKING THE BEARING Check Bearing Pitting rumbling Replace CHECKING THE PROPELLER SHAFT HOUSING Check Propeller shaft housing Cracks damage Replace 1 2 3 1 2 Stopper guide plate 90890 06501 Stopper guide stand 90890 06538 Bearing puller ass y 90890 06535 Driver rod L3 90890 06652 Needle bearing attachment 90890 06615 1 2 3 1 2 ...

Page 155: ...is essential that the oil seals are installed correctly as shown in the illustration If they are installed the wrong way round oil or water will leak out b 1 3 a 2 a 2 1 A Needle bearing position 31 0 31 5 mm 1 24 in Driver rod SS 90890 06604 Needle bearing attachment 90890 06615 Bearing depth plate 90890 06603 Oil seal position 6 0 6 5 mm 0 26 in Driver rod L3 90890 06652 Needle bearing attachmen...

Page 156: ...h its manu facturer s marks facing the reverse gear CAUTION Place a suitable base under the gear to pro tect it from damages CHECKING THE DOG CLUTCH Check Dog clutch Damage wear Replace CHECKING THE PROPELLER SHAFT Check Propeller shaft Damage wear Replace CHECKING THE SHIFT PLUNGER Check Shift plunger Wear Replace CHECKING THE SHIFT SPRING Check Spring Wear Replace 1 a 2 3 1 4 Maximum runout 0 1 ...

Page 157: ...DRIVE SHAFT REMOVING THE DRIVE SHAFT Step Job Part Q ty Remarks Propeller shaft housing Refer to PROPELLER SHAFT HOUS ING on page 6 7 1 Pinion gear nut 1 2 Pinion gear 1 3 Drive shaft 1 4 Forward gear 1 5 Drive shaft bearing 1 ...

Page 158: ...rench in position 3 Turn the drive shaft holder REMOVING THE DRIVE SHAFT BEARING Remove Taper roller bearing DISASSEMBLING THE FORWARD GEAR Remove Taper roller bearing Forward gear CAUTION Place a suitable base on the gear axle to prevent damage to the top of the axle 1 1 1 2 Drive shaft holder 3 90890 06517 Bearing inner race attachment 90890 06643 Bearing separator 90890 06534 1 1 1 1 2 ...

Page 159: ...ft Damage wear Replace CHECKING THE BEARINGS Check Bearings Pitting rumbling Replace ASSEMBLING THE FORWARD GEAR Install Forward gear Taper roller bearing INSTALLING THE DRIVE SHAFT BEARING Install Drive shaft bearing 1 1 Maximum runout 0 5 mm 0 020 in Bearing inner race attachment 90890 06644 Bearing inner race attachment 90890 06645 1 1 ...

Page 160: ...ion gear 2 Tighten Pinion gear nut Tightening steps 1 Apply 12mm wrench on the pinion gear nut 2 Support the lower case with rags to hold the wrench in position 3 Turn the drive shaft holder NOTE Tighten the pinion gear nut with the same tools that were used for removal 1 Drive shaft holder 3 90890 06517 T R Pinion gear nut 50 Nm 5 0 kgf m 37 ft lb 1 1 ...

Page 161: ...R CASE DISASSEMBLING THE LOWER CASE As required Step Job Part Q ty Remarks 1 Drive shaft bearing outer race 1 2 Pinion gear shim 3 Drive shaft sleeve 1 4 Needle bearing 1 5 Tapered roller bearing outer race 1 6 Forward gear shim ...

Page 162: ...aring outer race and shim s CHECKING THE DRIVE SHAFT SLEEVE Check Drive shaft sleeve Damage wear Replace 1 3 2 1 2 Stopper guide plate 90890 06501 Bearing puller ass y 90890 06535 Stopper guide stand 90890 06538 Driver rod L3 90890 06652 Needle bearing attachment 90890 06615 Stopper guide plate 90890 06501 Bearing puller ass y 90890 06535 1 2 3 1 2 1 2 ...

Page 163: ...all the drive shaft needle bearing with the manufactuer s marks facing up 3 Install Pinion gear shim s Drive shaft bearing outer race 1 2 1 3 2 a Bearing outer race attachment 90890 06622 Driver rod LL 90890 06605 Depth 185 0 186 0 mm 7 32 in Needle bearing attachment 90890 06615 Driver rod SL 90890 06602 Bearing depth plate 90890 06603 1 2 a 1 2 3 1 2 a b Driver rod LS 90890 06606 Bearing outer r...

Page 164: ...embling with the original case and inner parts Shim calculations are required when reassembling with the original inner parts and a new case the difference between the original inner parts and the new case Measurements and adjustments are required when replacing the inner part s ...

Page 165: ...wing nuts contact the fixing plate tighten them another 1 4 of a turn 2 Install the pinion gear and pinion gear nut 3 Measure M NOTE Measure the clearance between the pinion height gauge and the pinion as shown Perform the same measurement at three points on the pinion Find the average of the measurements M When using the digital caliper be sure to place it at right angles to the pinion Otherwise ...

Page 166: ...ive then add the P value to the measurement Example If M is 28 30 mm and P is 5 then T3 28 30 mm 27 mm 5 100 mm 1 3 mm 0 05 mm 1 25 mm 0 049 in If M is 28 24 mm and P is 3 then T3 28 24 mm 27 mm 3 100 mm 1 24 mm 0 03 mm 1 27 mm 0 05 in 5 Select the pinion gear shim s T3 Pinion gear shim thickness T3 M 27 mm P 100 mm Calculated numeral at 1 100th place Using shim more than or less 1 10 1 20 1 2 1 2...

Page 167: ...ge of the measurements M When using the digital caliper be sure to place it at right angles to the shim ming plate Otherwise measurement will be incor rect 2 Calculate the forward gear shim thick ness T1 NOTE F is the deviation of the lower case dimension from standard It is stamped on the trim tab mounting surface of the lower case in 0 01 mm units If the F mark is missing or unreadable assume an...

Page 168: ... in If M is 16 26 mm and F is 3 then T1 17 5 mm 3 100 16 26 mm 17 5 mm 0 03 16 26 mm 1 21 mm 0 048 in 3 Select the forward gear shim s T1 Calculated numeral at 1 100th place Using shim more than or less 1 00 1 10 1 0 1 10 1 20 1 1 1 20 1 30 1 2 1 30 1 40 1 3 1 40 1 50 1 4 Available shim thickness 1 0 1 1 1 2 1 3 and 1 4 mm ...

Page 169: ...ure to place it at right angles to the shim ming plate Otherwise measurement will be incor rect 2 Calculate the reverse gear shim thick ness T2 NOTE R is the deviation of the lower case dimension from standard It is stamped on the anode mounting surface of the lower case in 0 01 mm units If the R mark is missing or unreadable assum a R value of 0 and check the backlash when the unit is assembled I...

Page 170: ... mm 0 050 in If M2 is 78 75 mm and R is 3 then T2 80 mm 3 100 78 75 mm 80 mm 0 03 mm 78 75 mm 1 22 mm 0 048 in 3 Select the reverse gear shim s T2 Calculated numeral at 1 100th place Using shim more than or less 1 00 1 10 1 0 1 10 1 20 1 1 1 20 1 30 1 2 1 30 1 32 1 3 Available shim thickness 1 0 1 1 1 2 and 1 3 mm ...

Page 171: ...cklashes are smaller than specifica tion the pinion gear may be too low MEASURING THE FORWARD GEAR BACKLASH 1 Measure Forward gear backlash Out of specification Adjust Measuring steps 1 Set the shift rod into the neutral posi tion 2 Install the propeller shaft housing puller so it pushes against the propeller shaft Forward gear backlash 0 31 0 72 mm 0 012 0 028 in Bearing housing puller claw 90890...

Page 172: ...lash 2 Adjust Forward gear backlash Remove or add shim s M Measurement MEASURING THE REVERSE GEAR BACKLASH 1 Measure Reverse gear backlash Out of specification Adjust Backlash indicator 90890 06706 Magnet base plate 90890 07003 Dial gauge set 90890 01252 Magnet base 90890 06705 Forward gear backlash Shim thickness Less than 0 31 mm 0 012 in To be decreased by 0 52 M 0 49 More than 0 72 mm 0 028 in...

Page 173: ...sh indi cator 5 Slowly turn the drive shaft clockwise and counterclockwise When the drive shaft stops in each direction measure the backlash 2 Adjust Reverse gear backlash Remove or add shim s M Measurement 1 T R Propeller nut 5 N m 0 5 kgf m 3 7 ft lb Backlash indicator 90890 06706 Magnet base plate 90890 07003 Dial gauge set 90890 01252 Magnet base 90890 06705 Reverse gear backlash Shim thicknes...

Page 174: ......

Page 175: ...TOR 7 8 REMOVING THE BRACKET 7 11 CHECKING THE SHIFT ACTUATOR 7 11 ASSEMBLING THE SHIFT ACTUATOR 7 12 UPPER CASE 7 14 REMOVING THE UPPER CASE 7 14 CHECKING THE UPPER CASE 7 16 INSTALLING THE UPPER CASE 7 16 DISASSEMBLING THE UPPER CASE 7 17 CHECKING THE EXHAUST MANIFOLD 7 18 ASSEMBLING THE UPPER CASE 7 18 STEERING ARM 7 19 REMOVING THE STEERING ARM 7 19 CHECKING THE STEERING ARM 7 20 INSTALLING TH...

Page 176: ...ING HANDLE Step Job Part Q ty Remarks 1 Throttle cable 1 2 Throttle cable 1 3 Grommet 1 4 Bolt with washer 1 5 Bolt with washer 1 6 Steering handle cover 1 7 Collar 1 8 Collar 1 9 Plain washer 2 10 Wave washer 1 11 Screw 1 12 Handle 1 13 Washer 1 Continued on next page ...

Page 177: ...STEERING HANDLE BRKT 7 2 E Step Job Part Q ty Remarks 14 Compression spring 1 15 Bushing 1 16 Bolt 1 17 Self locking nut 1 18 Steering friction 1 19 Throttle lever 1 20 Steering handle 1 1 ...

Page 178: ...SEMBLING THE STEERING HANDLE 1 Install Steering handle 1 Throttle lever Throttle friction 2 Connect Throttle cable loose cable side Throttle cable tight cable side NOTE Connect the inner cable end in the groove and fit the outer cable end into the hole Apply Yamaha grease A water resis tant grease to the throttle lever and throttle cable 1 2 3 1 2 3 1 2 ...

Page 179: ... it 4 Install Plain washer Wave washer Collar Steering handle Collar Steering handle cover Bolt NOTE Apply Yamaha grease A water resistant grease to the throttle cables washers and the steering handle crown 5 Install Throttle cables through bottom cowling Grommet NOTE Pass the throttle cables through the steer ing handle on the steering bracket Be sure the throttle cable is routed correctly 1 2 3 ...

Page 180: ...HE BOTTOM COWLING Step Job Part Q ty Remarks 1 Nut 4 2 Collar 4 3 Grommet 4 4 Washer 4 5 Bottom cowling 1 6 Grommet 1 7 Engine stop switch 1 8 Choke knob 1 9 Grommet 1 10 Grommet 1 11 Grommet 1 12 Spring pin 1 13 Throttle lever 1 Continued on next page ...

Page 181: ...OTTOM COWLING BRKT 7 6 E Step Job Part Q ty Remarks 14 Bushing 2 15 Throttle control shaft 1 16 Friction spacer 1 17 Bolt with washer 1 18 Clamp lever 2 1 19 Bushing 2 20 Wave washer 1 21 Clamp lever 1 1 ...

Page 182: ...OTE Apply Yamaha grease A water resistant grease or replace parts as required INSTALLING THE BOTTOM COWLING 1 Install Bushing Throttle control shaft Throttle lever Spring pin NOTE Always use the new spring pin 2 Install Bottom cowling Nuts NOTE Apply Yamaha grease A water resistant grease to the clamp lever shaft 1 2 3 4 1 1 2 1 2 3 4 1 2 ...

Page 183: ...BLING THE SHIFT ACTUATOR Step Job Part Q ty Remarks 1 Rubber seal 1 2 Rubber seal 2 1 3 Bolt with washer 4 4 Nut 1 5 Washer 1 6 Bracket 1 7 Gasket 1 8 Nut 2 9 Washer 2 10 Bolt 2 11 Bolt with washer 1 12 Bracket 1 13 Dowel pin 1 Continued on next page ...

Page 184: ...4 Bushing 2 1 15 Compression spring 1 16 Compression spring 1 17 Shift cam plunger 1 18 Cotter pin 1 Not reusable 19 Washer 2 20 Cotter pin 1 Not reusable 21 Washer 1 22 Joint 1 23 Bolt 1 24 Shift lever 1 25 Grommet 1 26 Cam plate 1 Continued on next page ...

Page 185: ...art Q ty Remarks 27 Bushing 2 28 Grease nipple 1 29 Cotter pin 1 Not reusable 30 Washer 1 31 Plate washer 2 32 Shift rod 1 1 33 Spring pin 1 Not reusable 34 Shift rod lever 1 35 Plate washer 2 36 Collar 1 37 Shift rod 1 38 Torsion spring 1 ...

Page 186: ...ttom side of the upper case CHECKING THE SHIFT ACTUATOR 1 Check Shift lever Shift cam plunger Cam plate Joint Shift rod lever Shift rod Shift rod 1 Wear damage Replace NOTE Apply Yamaha grease A water resistant grease or replace parts as required 2 Check Bracket Bracket remote control attach ment Crack damage Replace 1 2 2 1 2 3 4 5 6 7 1 2 ...

Page 187: ... Cotter pin Grease nipple NOTE Always use the new spring pin and the cotter pin Apply Yamaha grease A water resis tant grease to the collar inner surface grease nipple and shift rod 1 2 Hook Torsion spring NOTE Hook it onto the shift rod lever and the bracket 3 Install Cam plate NOTE Apply Yamaha grease A water resistant grease to the cam plate shaft 1 1 2 1 2 3 4 5 6 7 8 1 1 ...

Page 188: ...er resistant grease to the shift cam plunger 5 Install Shift lever Bolt Arm 6 Install Bracket to upper casing Bolts Nut mount rubber front upper Rubber seal over the bracket 1 2 1 4 3 2 2 T R Bolt 11 N m 1 1 kgf m 8 1 ft lb T R Bolt 11 N m 1 1 kgf m 8 1 ft lb Nut 17 N m 1 7 kgf m 13 ft lb 1 2 1 2 3 2 1 2 3 4 2 3 ...

Page 189: ...t Q ty Remarks 1 Bolt with washer 2 2 Nut 2 3 Bolt with washer 2 4 Nut 2 5 Bolt with washer 2 6 Lower mount rubber housing 2 7 Mount rubber side lower 2 8 Lower mount cover 1 9 Mount rubber front lower 1 10 Nut 2 11 Washer 2 12 Upper case 1 13 Nut 2 Continued on next page ...

Page 190: ...UPPER CASE 7 15 E BRKT Step Job Part Q ty Remarks 14 Bolt 2 15 Washer 2 16 Nut 2 17 Mount rubber side upper 2 18 Gasket 4 19 Bolt with washer 2 20 Mount rubber front upper 1 ...

Page 191: ...nt rubber side upper with gaskets Nut Upper case to swivel bracket Nut side upper Mount rubber side lower Mount rubber front lower Lower mount cover Lower mount rubber housing NOTE Make sure the lower mount rubber hous ing is installed with the UP mark point ing upward T R Nut 17 N m 1 7 kgf m 13 ft lb Bolt lower mount rubber housing 17 N m 1 7 kgf m 13 ft lb 1 2 1 2 3 4 5 6 7 8 9 5 9 ...

Page 192: ...E Step Job Part Q ty Remarks 1 Bolt 1 2 Exhaust guide 1 3 Bolt 4 4 Exhaust manifold 1 5 Exhaust seal 2 1 Not reusable 6 Exhaust seal 1 1 Not reusable 7 Cotter pin 1 Not reusable 8 Gasket 1 9 Gasket 1 Not reusable 10 Water tube 1 11 Water seal rubber 1 ...

Page 193: ...E UPPER CASE 1 Install Exhaust manifold Exhaust guide Exhaust seals Gasket NOTE Always use new gaskets and exhaust seals If old ones are used gas leakage may result due to invisible scratches or stretches 2 Install Water seal rubber Water tube NOTE Install the water seal rubber so that it aligns with the locating hole in the upper case 1 2 1 2 3 4 a ...

Page 194: ... ARM REMOVING THE STEERING ARM Step Job Part Q ty Remarks 1 Bolt 1 2 Seal rubber 1 3 Bolt 4 4 Bracket 1 5 Dowel pin 2 6 Steering pivot shaft 1 7 Washer 1 8 Bushing 1 9 Friction piece 1 10 Bushing 1 11 O ring 1 Not reusable 12 Bushing 1 ...

Page 195: ...stall Bracket Steering pivot shaft Bushing Bushing Friction piece O ring Washer Washer Dowel pin to pivot shaft Bolt Bolt steering friction NOTE Always use the new O ring Apply Yamaha grease A water resis tant grease to the busing O ring and the grease nipples After installing the steering bracket make sure the movement of steering pivot shaft by moving it 9 10 11 1 2 3 4 5 1 2 3 4 5 6 7 8 9 10 11...

Page 196: ...CKETS Step Job Part Q ty Remarks 1 Tension spring 1 2 Tilt rod 1 3 Conical spring 1 4 Nut 1 5 Washer 1 6 Bolt 1 7 Collar 1 8 Clamp bracket cap 2 9 Nut 2 10 Clamp bracket plate 1 11 Clamp bracket 1 1 12 Clamp bracket 2 1 13 Clamp bracket bolt 1 Continued on next page ...

Page 197: ...emarks 14 Washer 2 15 Bushing 2 16 Tilt lever cover 1 17 Tilt lever 1 18 Torsion spring 1 19 Circlip 1 20 Pin 1 21 Spring return lever 1 22 Tilt lock rod 1 23 Tilt lock rod 1 24 Cotter pin 1 25 Pin 1 26 Tilt lock plate outer 2 Continued on next page ...

Page 198: ...RKT Step Job Part Q ty Remarks 27 Pin 2 28 Tension spring 2 29 Bolt 2 30 Shallow water lever 1 31 Cover 1 32 Tilt lock plate inner 1 33 Grease nipple 4 34 Swivel bracket 1 35 Spring pin 1 36 Stopper knob 1 37 Stopper shaft 1 ...

Page 199: ... 2 Check Tilt lock plate outer Tilt lock plate inner Shallow water lever Tension spring Tension springs Bent crack damage Replace 3 Check Tilt rod Bent damage Replace Conical spring Crack damage Replace 4 Check Tilt lever 1 Tilt lever 2 Tilt lock rod Torsion spring Crack damage Replace 5 Check Bushing Wear damage Replace 1 2 3 1 2 3 4 5 1 2 1 2 3 4 1 ...

Page 200: ...r outer rear side Pin Cotter pin NOTE Always use the new cotter pin Apply grease to parts when specified 2 Install Swivel bracket Pin Tilt lever Circlip Tilt lock rod hook to inner tilt lock plate Tilt lock rod hook to tilt lever 1 Torsion spring NOTE Always use the new circlip Apply water resistant grease to the pin and tilt levers 1 2 3 4 5 6 8 7 1 2 3 4 5 6 7 1 2 3 4 5 6 7 8 ...

Page 201: ...he transom clamp screw stopper shaft and the grease nipple 4 Install Clamp bracket bolt Clamp bracket starboard side Washer Swivel bracket Torsion spring Tilt lever Washer Clamp bracket port side Nut clamp bracket bolt Bolt Collar Nut Tilt rod with conical spring Tension spring NOTE Place the tilt lever inside the clamp bracket port side as shown 6 8 1 6 5 T R Nut 45 N m 4 5 kgf m 33 ft lb 1 2 3 4...

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Page 203: ... THE SPARK PLUGS 8 5 CHECKING THE IGNITION SPARK GAP 8 5 CHECKING THE SPARK PLUG CAPS 8 6 REMOVING THE SPARK PLUG CAPS STANDARD TYPE 8 6 INSTALLING THE SPARK PLUG CAPS STANDARD TYPE 8 6 CHECKING THE IGNITION COILS 8 7 CHECKING THE CHARGE COIL 8 8 CHECKING THE PULSER COIL 8 9 CDI UNIT 8 10 CHECKING THE CDI UNIT 8 11 IGNITION CONTROL SYSTEM 8 13 WIRING DIAGRAM 8 13 CHECKING THE ENGINE STOP SWITCH 8 ...

Page 204: ...C 8 1 E 8 ELECTRICAL COMPONENT 1 Ignition coil B Black 2 Charge coil Br Brown 3 Pulser coil G Green 4 CDI unit L Blue 5 Engine stop switch W White 6 Lighting coil B O Black Orange B W Black White W B White Black W R White Red ...

Page 205: ... wires NOTE When checking the condition of the ignition system it is useful to know the peak voltage Cranking speed is dependant on many factors e g fouled or weak spark plugs a weak battery If one of three is defective the peak voltage will be lower than specification If the peak voltage measurement is not within specification the engine will not operate properly PEAK VOLTAGE ADAPTER NOTE The pea...

Page 206: ... fol lowing tests Measuring steps 1 Connect the peak voltage adapter probes to the connectors 2 Start or crank the engine and observe the measurement MEASURING A LOW RESISTANCE When measuring a resistance of 10Ω or less with the digital tester the correct measure ment cannot be obtained because of the tester s internal resistance To obtain the correct value subtract the internal resistance from th...

Page 207: ...ION SYSTEM 8 4 E ELEC IGNITION SYSTEM WIRING DIAGRAM 1 Spark plug B Black 2 Ignition coil Br Brown 3 Charge coil L Blue 4 Pulser coil B O Black Orange 5 CDI unit B W Black White W B White Black W R White Red ...

Page 208: ...way since this test can produce sparks Check Ignition spark gap Below specification Check the ignition system Checking steps 1 Remove the spark plugs from the engine 2 Connect a spark plug cap to the ignition tester 3 Adjust the ignition spark gap to 11 mm 0 43 in by turning the adjust knob NOTE Be careful so that the spark gap does not come excessively off the measuring posi tion 11 mm 0 43 in St...

Page 209: ...is not with the ignition system but pos sibly with the spark plug s or another component CHECKING THE SPARK PLUG CAPS Check Spark plug cap Crack damage Replace REMOVING THE SPARK PLUG CAPS STANDARD TYPE Removing steps 1 Remove the spark plug cap by pull ing the cap and remove the plug cup spring from the high tension cable INSTALLING THE SPARK PLUG CAPS STANDARD TYPE Installing steps 1 Cut about l...

Page 210: ...OILS 1 Check Ignition coil Crack damage Replace 2 Measure Ignition coil resistance Out of specification Check the peak voltage charge coil pulser coil CDI unit Replace NOTE When making secondary leads resistance test disconnect spark plug cap Ignition coil resistance Primary B W B Secondary B output 0 18 0 24 Ω Ω Ω Ω 2 70 3 70 kΩ Ω Ω Ω 4 b c 1 ...

Page 211: ...voltage measurement connect the adaptor as the illustration for the open circuit and as the illustration for the closed circuit Charge coil resistance Br L 342 418 Ω Ω Ω Ω Charge coil output peak voltage Br L r r r r m m m mi i i in n n n C C C Cr r r ra a a an n n nk k k ki i i in n n ng g g g 1 1 1 1 5 5 5 50 0 0 00 0 0 0 3 3 3 3 5 5 5 50 0 0 00 0 0 0 O O O Op p p pe e e en n n ne e e ed d d d C...

Page 212: ...ion for the closed circuit Pulser coil resistance W R B 1 W B B 2 311 381 Ω Ω Ω Ω P P P Pu u u ul l l ls s s se e e er r r r c c c co o o oil il il il o o o ou u u ut t t tpu pu pu put t t t p p p pe e e ea a a ak k k k v v v vo o o ol l l lt t t ta a a ag g g ge e e e W W W W R R R R B B B B 1 1 1 1 W W W W B B B B B B B B 2 2 2 2 r r r r m m m mi i i in n n n C C C Cr r r ra a a an n n nk k k ki...

Page 213: ...IGNITION SYSTEM 8 10 E ELEC CDI UNIT 1 CDI unit B Black Br Brown L Blue W White B O Black Orange B W Black White W B White Black W R White Red ...

Page 214: ...ry from meter to meter especially with elec tronic digital meters For some testers polarity of leads is reversed Measuring steps 1 Disconnect the CDI unit leads from the wire harness 2 Connect the pocket tester Ω 1K to the CDI unit as shown list Refer to CDI UNIT on page 8 10 NOTE There is a point at which the pointer swings greatly and swings back Read the point where the point has returned to st...

Page 215: ...ltage measurement connect the adaptor as the illustration for the open circuit and as the illustration for the closed circuit CDI unit output peak voltage B O B B W B r r r r m m m mi i i in n n n C C C Cr r r ra a a an n n nk k k ki i i in n n ng g g g 1 1 1 1 5 5 5 50 0 0 00 0 0 0 3 3 3 3 5 5 5 50 0 0 00 0 0 0 O O O Op p p pe e e en n n ne e e ed d d d C C C Cl l l lo o o os s s se e e ed d d d ...

Page 216: ...IGNITION CONTROL SYSTEM ELEC 8 13 E IGNITION CONTROL SYSTEM WIRING DIAGRAM 1 CDI unit B Black 2 Engine stop switch W White ...

Page 217: ...TION CONTROL SYSTEM 8 14 E ELEC CHECKING THE ENGINE STOP SWITCH Check Continuity Out of specification Replace A B C Lead color White Black Remove the lock plate Install the lock plate Push the button A B C ...

Page 218: ...CHARGING SYSTEM ELEC 8 15 E CHARGING SYSTEM WIRING DIAGRAM 1 Lighting coil G Green ...

Page 219: ... specification Replace Lighting coil resistance G G 0 31 0 37 Ω Ω Ω Ω Lighting coil output peak voltage G G r r r r m m m mi i i in n n n C C C Cr r r ra a a an n n nk k k ki i i ing ng ng ng O O O Op p p pe e e en n n ne e e ed d d d C C C Cl l l lo o o os s s se e e ed d d d D D D D C C C C V V V V 4 4 4 4 6 6 6 6 r r r r m m m mi i i in n n n 1 1 1 1 5 5 5 50 0 0 00 0 0 0 3 3 3 3 5 5 5 50 0 0 0...

Page 220: ......

Page 221: ...E 1 2 3 4 5 6 7 8 9 TRBL ANLS CHAPTER 9 TROUBLE ANALYSIS TROUBLE ANALYSIS 9 1 TROUBLE ANALYSIS CHART 9 1 TROUBLE SHOOTING FOR PEAK VOLTAGE 9 4 ...

Page 222: ...retor vapor separator 7 The rigging and engine setting are correct 8 The engine is free from any Hull problem TROUBLE ANALYSIS CHART Trouble mode Check elements ENGINE WILL NOT START HARD STARTING ROUGH IDLING HIGH IDLING ENGINE STALLS POOR ACCELERATION ENGINE WILL NOT STOP POOR PERFORMANCE LIMITED ENGINE SPEED OVERHEATING LOOSE STEERING HARD SHIFTING IRREGULAR WARNING INDICATION POOR BATTERY CHAR...

Page 223: ... Shift rod joint Pin 6 Shift rod 6 Lower case 6 BRACKET UNIT Bracket 7 Rubber mount 7 Shift actuator 7 ELECTRICAL SYSTEMS Ignition system Spark plugs 8 Trouble mode Check elements ENGINE WILL NOT START HARD STARTING ROUGH IDLING HIGH IDLING ENGINE STALLS POOR ACCELERATION ENGINE WILL NOT STOP POOR PERFORMANCE LIMITED ENGINE SPEED OVERHEATING LOOSE STEERING HARD SHIFTING IRREGULAR WARNING INDICATIO...

Page 224: ...Charging system Lighting coil 8 Trouble mode Check elements ENGINE WILL NOT START HARD STARTING ROUGH IDLING HIGH IDLING ENGINE STALLS POOR ACCELERATION ENGINE WILL NOT STOP POOR PERFORMANCE LIMITED ENGINE SPEED OVERHEATING LOOSE STEERING HARD SHIFTING IRREGULAR WARNING INDICATION POOR BATTERY CHARGING Relative part Reference Chapter ...

Page 225: ... speed drops during acceleration Check the ignition system 1 Check the lead to ignition coil CDI unit pulser coil and charge coil NG OK Contamination Loose connection Corrosion Clean Correct 2 Check the spark gap NG OK Above specification Replace the spark plug 3 Check the plug cap resistance NG OK Out of specification Replace 4 Check the ignition coils resistance NG OK Out of specification Replac...

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Page 228: ...Printed on recycled paper Printed in Japan Oct 2000 0 3 1 EK25BMH YAMAHA MOTOR CO LTD ...

Page 229: ... Green white White black White red B Br G L R W B O B W G W W B W R G G G G W W W B B B B B B B B B W B W B O B W B W B W W R W R W B W B Br Br L B B W R W B Br L B L B W B O W R W B Br B B L Ignition coil 2 2 Ignition coil 1 1 Charge coil 3 Pulser coil 4 CDI unit 5 Engine stop switch 6 ...

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