Yamaha F2.5A Service Manual
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Yamaha F2.5A Service Manual

Yamaha F2.5A Service Manual

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F2.5A
SERVICE MANUAL
290470
69M-28197-3E-11
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Summary of Contents for Yamaha F2.5A

  • Page 1 F2.5A SERVICE MANUAL 290470 69M-28197-3E-11...

  • Page 2: Important Information

    NOTICE This manual has been prepared by Yamaha primarily for use by Yamaha dealers and their trained mechanics when performing maintenance procedures and repairs to Yamaha equipment. It has been written to suit the needs of persons who have a basic understanding of the mechanical and electrical concepts and procedures inherent in the work, for without such knowledge attempted repairs or service to the equipment could render it unsafe or unfit for use.

  • Page 3: Table Of Contents

    Contents General information INFO Specifications SPEC Periodic checks and adjustments Fuel system FUEL Power unit POWR Lower unit LOWR Bracket unit BRKT – Electrical systems ELEC Troubleshooting TRBL SHTG Index...

  • Page 5: General Information

    INFO General information How to use this manual ................. 1-1 Manual format.................... 1-1 Symbols..................... 1-2 Safety while working..................1-3 Fire prevention................... 1-3 Ventilation....................1-3 Self-protection ................... 1-3 Parts, lubricants, and sealants ..............1-3 Good working practices ................1-4 Disassembly and assembly ............... 1-4 Identification....................1-5 Applicable model ..................1-5 Serial number ....................

  • Page 6: How To Use This Manual

    INFO General information How to use this manual Manual format The format of this manual has been designed to make service procedures clear and easy to under- stand. Use the information below as a guide for effective and quality service. 1 Parts are shown and detailed in an exploded diagram and are listed in the components list.

  • Page 7: Symbols

    Symbols 7 to B in an exploded diagram indicate the grade of lubricant and the lubrication point. 7 Apply Yamaha 4-stroke motor oil A Apply low temperature resistant grease 8 Apply water resistant grease (Yamaha grease A) (Yamaha grease C) 9 Apply molybdenum disulfide grease...

  • Page 8: Safety While Working

    Parts, lubricants, and sealants Use only genuine Yamaha parts, lubricants, and sealants or those recommended by Yamaha, when servicing or repairing the out- board motor. Ventilation Gasoline vapor and exhaust gas are heavier than air and extremely poisonous.

  • Page 9: Good Working Practices

    Safety while working Disassembly and assembly 6. Keep a supply of clean, lint-free cloths for wiping up spills, etc. 1. Use compressed air to remove dust and dirt during disassembly. Good working practices Special service tools 2. Apply engine oil to the contact surfaces Use the recommended special service tools of moving parts before assembly.

  • Page 10: Identification

    INFO General information Identification Applicable model This manual covers the following model. Applicable model F2.5AMH Serial number outboard motor serial number stamped on a label attached to the port clamp bracket. 1 Model name 2 Approved model code 3 Transom height 4 Serial number Approved Starting...

  • Page 11: Features And Benefits

    Identification / Features and benefits Features and benefits Ignition system A simple and compact ignition system is adopted. In this ignition system, high voltage is induced in the secondary coil when the electric current produced by the primary coil and the permanent mag- net on the rotating flywheel is cut off.

  • Page 12: Blowby Gas Reburning System

    INFO General information Blowby gas reburning system The splash lubrication system splashes a large quantity of oil into the blowby gases. Therefore, a reburning system is incorporated to separate the oil from the blowby gases in two stages: first in the cylinder head and second in the intake silencer.

  • Page 13: Oil Check Window

    Features and benefits Oil check window The F2.5 is equipped with an oil check window to make engine oil level checks easier. The oil checking plate in the oil check window indicates the proper oil level when the outboard motor is in an upright position.

  • Page 14: Idle Silencer

    INFO General information Idle silencer The idle silencer is installed to the upper case to reduce exhaust noise and carbon deposits around the exhaust idle port. Exhaust gases are discharged into the idle silencer from the two upper holes in the upper case. The gases flow and eddy (swirl) inside the silencer and then are discharged from the exhaust idle port of the silencer into the atmosphere.

  • Page 15: Splash Lubrication System

    Features and benefits Splash lubrication system A simple splash lubrication system design is adopted. The splasher is driven by the oil splasher gear installed on the camshaft and splashes oil in the oil pan onto the internal parts of the crankcase. S69M1170 1-10 69M3E11...

  • Page 16: Low Vibration Tiller Handle

    INFO General information Low vibration tiller handle The tiller handle is installed near the center of the outboard motor for low vibration. To help reduce vibration transferring to the tiller handle, a rubber damper is used at the installation point of the handle. The tiller handle is equipped with a throttle indicator to indicate the throttle angle, an engine shut-off switch to turn the engine off in an emergency, and a throttle friction adjuster to adjust the friction of the throttle lever.

  • Page 17: Technical Tips

    Features and benefits / Technical tips Technical tips TCI system The TCI system operates as follows. Before ignition As the flywheel rotates, the primary coil generates a voltage and an electric current A. This electric current opens transistor Q1 and, as a result, an electric current B flows to the primary coil. S69M1200 Ignition As the flywheel continues to rotate, the voltage generated by the primary coil increases.

  • Page 18: Automatic Tilt Support And Steering Pivot Immobilization System

    INFO General information Automatic tilt support and steering pivot immobilization system The tilt support lever is constantly pushed against the clamp bracket by the force of a spring. When the outboard motor is fully tilted up in the forward steering position, the stopper linked to the tilt support lever is inserted into the swivel cutout.

  • Page 19: Cooling Water Flow Chart

    Technical tips Cooling water flow chart Cylinder Cylinder Crankcase block head Upper case Cooling water Upper case Thermostat (Top starboard pilot hole (Inside) side) Lower case Atmosphere Water pump exhaust port Cooling water Atmosphere : È inlet : É : Ê S69M1230 È...

  • Page 20: Propeller Selection

    INFO General information Propeller selection Predelivery checks The performance of a boat and outboard To make the delivery process smooth and motor will be critically affected by the size efficient, the predelivery checks should be and type of propeller you choose. Propellers completed as explained below.

  • Page 21: Checking The Engine Oil

    Propeller selection / Predelivery checks Checking the engine oil Checking the outboard motor 1. Check the oil level through the oil level mounting height window 1. 1. Check that the anti-cavitation plate is between the bottom of the boat and a maximum of 25 mm (1 in) a below it.

  • Page 22: Checking The Gear Shift And Throttle Operation

    INFO General information 2. Check that steering operates Checking the engine shut-off switch smoothly. 1. Check that the engine turns off when the engine stop switch is pushed or the engine shut-off cord is pulled from the engine shut-off switch. Checking the gear shift and throttle operation 1.

  • Page 23: Test Run

    Predelivery checks Test run Adjusting the engine idle speed 1. Start the engine, and then check that the Adjust the idle speed after completing the gear shift operates smoothly. break-in period. With the smallest engine and lowest output, 2. Check the engine idle speed after the the idle speed tends to rise by the reduction engine has been warmed up.
  • Page 24 INFO General information 4. Turn the throttle stop screw 2 in direc- tion a or b until the specified idle speed is obtained. NOTE: • To increase the idle speed, turn the throttle stop screw in direction a. • To decrease the idle speed, turn the throttle stop screw in direction b.

  • Page 25: Specifications

    SPEC Specifications General specifications................... 2-1 Maintenance specifications ................2-3 Power unit....................2-3 Electrical ....................2-5 Dimensions....................2-6 Tightening torques..................2-8 Specified torques..................2-8 General torques..................2-9 69M3E11...

  • Page 26: General Specifications

    SPEC Specifications General specifications Model Item Unit F2.5AMH Dimension Overall length mm (in) 623 (24.5) Overall width mm (in) 345 (13.6) Overall height mm (in) 1,021 (40.2) mm (in) 1,148 (45.2) Boat transom height mm (in) 381 (15.0) mm (in) 508 (20.0) Weight* kg (lb)
  • Page 27 General specifications Model Item Unit F2.5AMH Fuel and oil Fuel type Regular unleaded gasoline Fuel rating PON* Fuel tank capacity L (US gal, 0.9 (0.24, 0.20) lmp gal) Engine oil type 4-stroke motor oil Engine oil grade SE, SF, SG, SH, or SJ 10W-30 or 10W-40 Engine oil quantity L (US gal,...

  • Page 28: Maintenance Specifications

    SPEC Specifications Maintenance specifications Power unit Model Item Unit F2.5AMH Power unit Minimum compression 700 (7.0, 102) pressure* (kgf/cm , psi) Cylinder head Warpage limit mm (in) 0.1 (0.004) (lines indicate straightedge position) Cylinder Bore size mm (in) 54.000–54.015 (2.1260–2.1266) Taper limit mm (in) 0.08 (0.0031)
  • Page 29 Maintenance specifications Model Item Unit F2.5AMH Oil ring Dimension B mm (in) 1.87–1.95 (0.0736–0.0768) Dimension T mm (in) 2.10–2.40 (0.0827–0.0945) End gap mm (in) 0.20–0.70 (0.0079–0.0276) Side clearance mm (in) 0.06–0.16 (0.0024–0.0063) Camshaft Intake and mm (in) 26.139–26.239 (1.0290–1.0330) exhaust (A) Intake and mm (in) 21.950–22.050 (0.8642–0.8681)

  • Page 30: Electrical

    SPEC Specifications Model Item Unit F2.5AMH Connecting rod Small end inside diameter mm (in) 12.006–12.020 (0.4727–0.4732) Big end inside diameter mm (in) 24.000–24.015 (0.9449–0.9455) Big end side clearance mm (in) 0.2–0.6 (0.008–0.024) Crankpin oil clearance mm (in) 0.016–0.046 (0.0006–0.0018) Crankshaft Crankshaft journal diameter mm (in) 21.980–21.993 (0.8654–0.8659)

  • Page 31: Dimensions

    Maintenance specifications Dimensions Exterior mm (in) S: 636 (25.0) 366 (14.4) L: 761 (30.0) 309 (12.2) 93 (3.7) 315 (12.4) 57 (2.2) 167 (6.6) 215 (8.5) S69M2010 69M3E11...
  • Page 32 SPEC Specifications Clamp bracket mm (in) 69 (2.7) 69 (2.7) 56 (2.2) 56 (2.2) 21.8 (0.9) 58 (2.3) S69M2020 69M3E11...

  • Page 33: Tightening Torques

    Maintenance specifications / Tightening torques Tightening torques Specified torques Tightening torques Part to be tightened Thread size N·m kgf·m ft·lb Power unit Anode screw Choke knob nut — Connecting rod cap Crankcase bolt 10.3 Cylinder head bolt 22.1 Cylinder head cover bolt Drive shaft oil seal housing bolt Exhaust probe bolt 14.8...

  • Page 34: General Torques

    SPEC Specifications General torques This chart specifies tightening torques for standard fasteners with a standard ISO thread pitch. Tightening torque specifications for special components or assemblies are provided in applicable sections of this man- ual. To avoid warpage, tighten multi-fastener assemblies in a crisscross fashion and pro- gressive stages until the specified torque is reached.
  • Page 35 Periodic checks and adjustments Special service tools ..................3-1 Maintenance interval chart................3-2 Fuel system ....................3-3 Checking the fuel line ................3-3 Checking the fuel filter ................3-3 Power unit....................... 3-3 Checking the engine oil ................3-3 Changing the engine oil................3-4 Checking the valve clearance..............3-4 Checking the spark plug ................3-5 Checking the thermostat................3-6 Checking the cooling water passage............3-7...

  • Page 36: Chk Adj

    Periodic checks and adjustments Special service tools Digital tachometer 90890-06760 Timing light 90890-03141 Leakage tester 90890-06840 69M3E11...

  • Page 37: Maintenance Interval Chart

    Special service tools / Maintenance interval chart Maintenance interval chart Use the following chart as a guideline for general maintenance. Adjust the maintenance intervals according to the operating conditions of the outboard motor. Initial Every Refer to Item Remarks 10 hours 50 hours 100 hours 200 hours...

  • Page 38: Fuel System

    Periodic checks and adjustments Fuel system Power unit Checking the fuel line Checking the engine oil 1. Check the fuel tank 1 for leaks. Replace 1. Place the outboard motor in an upright if necessary. Also, check the fuel hose 2 position.

  • Page 39: Changing The Engine Oil

    Fuel system / Power unit Changing the engine oil Recommended engine oil: 1. Remove the oil filler cap 1. 4-stroke motor oil API: SE, SF, SG, SH, or SJ SAE: 10W-30 or 10W-40 Oil quantity: 0.35 L (0.09 US gal, 0.08 Imp gal) 5.

  • Page 40: Checking The Spark Plug

    Periodic checks and adjustments 5. Loosen the rocker arm locknuts A, and 3. Slowly pull the starter rope to set the pis- then turn the rocker arm pivot B until the ton position to TDC of the compression stroke. specified valve clearance is obtained. NOTE: NOTE: •...

  • Page 41: Checking The Thermostat

    Power unit 3. Clean the electrodes 2 with a spark plug Spark plug: cleaner or wire brush. Replace the spark 25 N·m (2.5 kgf·m, 18.4 ft·lb) plug if necessary. Checking the thermostat 1. Remove the fuel tank 1, manual starter 2, flywheel magnet cover 3, thermostat cover 4, and thermostat 5.

  • Page 42: Checking The Cooling Water Passage

    Periodic checks and adjustments 4. Check the thermostat valve opening at specified water temperatures. Replace if out of specification. Control system Checking the engine idle speed 1. Start the engine and warm it up for 5 min- Water utes. Valve lift a temperature 2.

  • Page 43: Checking The Ignition Timing

    Power unit / Control system 3. Turn the throttle stop screw 2 in direc- 7. After adjusting the idle speed, rev the tion a or b until the specified engine engine a few times and let it idle for at idle speed is obtained.

  • Page 44: Chk Adj

    Periodic checks and adjustments Checking the TCI unit air gap 1. Remove the fuel tank 1, manual starter 2, and flywheel magnet cover 3. 4. Tighten the bolts, and then check the TCI unit air gap. Adjust if necessary. Lower unit Checking the gear oil level 1.

  • Page 45: Changing The Gear Oil

    Control system / Lower unit Changing the gear oil 5. Check the oil for metal, discoloration, and viscosity. Check the internal parts of the 1. Fully tilt the outboard up, and then sup- port it with the tilt stop lever 1. lower case if necessary.

  • Page 46: Checking The Lower Unit For Air Leakage

    Periodic checks and adjustments Checking the lower unit for air leakage 1. Remove the check screw 1, and then install the special service tool. General Checking the anodes 1. Check the anodes for scales, grease, or oil. Clean if necessary. Leakage tester: 90890-06840 2.

  • Page 47: Lubricating The Outboard Motor

    Lower unit / General Lubricating the outboard motor 1. Apply water resistant grease to the areas shown. NOTE: Apply grease to the grease nipple until it flows from the bushings a. 2. Apply corrosion resistant grease to the area shown. 3-12 69M3E11...
  • Page 48 Periodic checks and adjustments — MEMO — 3-13 69M3E11...

  • Page 49: Fuel

    FUEL Fuel system Special service tools ..................4-1 Hose routing ....................4-2 Fuel and blowby hoses................4-2 Fuel tank ......................4-3 Carburetor and intake silencer ..............4-4 Carburetor....................... 4-5 Draining the fuel ..................4-7 Checking the fuel tank and fuel filler cap........... 4-7 Checking the fuel filter ................4-7 Checking the fuel cock ................4-7 Checking the carburetor ................4-7 Assembling the carburetor.................

  • Page 50: Fuel System

    FUEL Fuel system Special service tools Digital tachometer 90890-06760 Pilot screw wrench 90890-03154 69M3E11...

  • Page 51: Hose Routing

    Special service tools / Hose routing Hose routing Fuel and blowby hoses S69M4000 1 Fuel hose 2 Blowby hose 3 Blowby hose 69M3E11...

  • Page 52: Fuel Tank

    FUEL Fuel system Fuel tank S69M4010 Part name Q’ty Remarks Fuel tank Fuel filter Fuel filler cap Stopper Chain Stopper Gasket M6 × 35 mm Bolt Grommet Collar Clip Fuel hose Damper Clip 69M3E11...

  • Page 53: Carburetor And Intake Silencer

    Fuel tank / Carburetor and intake silencer Carburetor and intake silencer S69M4020 Part name Q’ty Remarks Carburetor Intake silencer Blowby hose M6 × 75 mm Bolt Collar O-ring Not reusable Plastic tie Not reusable Hose Fuel cock Gasket Not reusable Gasket Gasket Not reusable...

  • Page 54: Carburetor

    FUEL Fuel system Carburetor È S69M4032 Part name Q’ty Remarks Carburetor body ø4 × 10 mm Screw Cover Gasket Not reusable ø4 × 8 mm Screw O-ring Not reusable Fuel cock Main nozzle Main jet Pilot jet Bushing Float Float pin ø4 ×...
  • Page 55 Carburetor È S69M4032 Part name Q’ty Remarks ø4 × 10 mm Screw Drain screw Spring O-ring Not reusable Pilot screw È For Europe 69M3E11...

  • Page 56: Draining The Fuel

    FUEL Fuel system Draining the fuel Checking the fuel tank and fuel filler WARNING 1. Check the fuel tank and fuel filler cap for Before removing the fuel tank, fuel hose, cracks, leaks, or damage. Replace if nec- and carburetor, let the fuel drain com- essary.
  • Page 57 Carburetor 2. Blow compressed air into all passages and jets. 5. Check the float for deterioration. Replace if necessary. CAUTION: • Direct the compressed air downward, otherwise cleaning solvent may be blown into your eyes or small parts of the carburetor may be blown off. •...

  • Page 58: Assembling The Carburetor

    FUEL Fuel system Assembling the carburetor È 1. Install the main nozzle 1, main jet 2, pilot jet 3, and bushing 4 to the carbu- retor body as shown. S69M4130 È For Europe Pilot screw wrench 0: 90890-03154 Pilot screw setting: 2–3 turns out S69M4110 Installing the carburetor 2.

  • Page 59: Installing The Throttle Cable

    Carburetor 2. Install the choke wire 4 to the choke lever 5 of carburetor. S69M4190 Adjusting the pilot screw 1. Start the engine and warm it up for 5 min- Installing the throttle cable utes. 1. Turn the throttle grip to the fully closed 2.
  • Page 60 FUEL Fuel system 3. Turn the pilot screw 2 in direction a until it is lightly seated, then in direction b to the specified number of turns. È È S69M4200 È For Europe Pilot screw wrench 3: 90890-03154 Pilot screw setting: 2–3 turns out 4.

  • Page 61: Powr

    POWR Power unit Special service tools ..................5-1 Power unit....................... 5-3 Checking the compression pressure ............5-7 Disassembling the manual starter ............. 5-7 Checking the spiral spring ................. 5-8 Assembling the manual starter ..............5-8 Removing the power unit.................5-10 Cylinder head ....................5-12 Removing the cylinder head ..............5-14 Checking the rocker arms................5-15 Checking the push rod guide..............

  • Page 62: Power Unit

    POWR Power unit Special service tools Compression gauge Valve guide remover/installer 90890-03160 90890-06801 Flywheel holder Valve guide reamer 90890-06522 90890-06804 Flywheel puller Valve seat cutter holder 90890-06521 90890-06316 Valve spring compressor Valve seat cutter 90890-04019 90890-06312, 90890-06315, 90890-06328 Valve spring compressor attachment Crank stand alignment 90890-06320 90890-03107...
  • Page 63 Special service tools Stopper guide plate Needle bearing attachment 90890-06501 90890-06613 Stopper guide stand Driver rod LS 90890-06538 90890-06606 Bearing puller Bearing outer race attachment 90890-06535 90890-06624 Bearing puller claw 1 Bushing attachment 90890-06536 90890-06649 Driver rod L3 Piston slider 90890-06652 90890-06843 69M3E11...

  • Page 64: Power Unit

    POWR Power unit Power unit Part name Q’ty Remarks Starter case Flywheel magnet cover Spiral spring Sheave drum Drive pawl Drive plate Screw Choke knob assembly Stopper Manual starter handle Damper Starter rope Spring Plate M6 × 60 mm Bolt 69M3E11...
  • Page 65 Power unit Part name Q’ty Remarks TCI unit Flywheel magnet Starter pulley Spark plug Grommet Clamp M6 × 25 mm Bolt M6 × 12 mm Bolt Washer Woodruff key Spark plug cap 69M3E11...
  • Page 66 POWR Power unit Part name Q’ty Remarks Power unit Gasket Not reusable Bottom cowling 1 Bottom cowling 2 Carrying handle Bracket Thermostat cover Gasket Not reusable Thermostat Oil filler cap O-ring Anode ø5 × 25 mm Screw Grommet Damper Dowel Fuel cock lever 69M3E11...
  • Page 67 Power unit Part name Q’ty Remarks ø5 × 7 mm Screw Cooling water hose Throttle cable M6 × 36 mm Bolt M6 × 16 mm Bolt M6 × 20 mm Bolt M6 × 20 mm Bolt M6 × 20 mm Bolt ø5 ×...

  • Page 68: Checking The Compression Pressure

    POWR Power unit Checking the compression pressure NOTE: 1. Start the engine, warm it up for 5 min- • If the compression pressure increases, utes, and then turn it off. check the piston and piston rings for wear. Replace if necessary. 2.

  • Page 69: Checking The Spiral Spring

    Power unit 3. Remove the sheave drum 4. Checking the spiral spring 1. Check the spiral spring for cracks, bends, or damage. Replace if necessary. S69M5090 WARNING S69M5120 The spiral spring can pop out. Pull the Assembling the manual starter starter rope, and then pull out the sheave 1.
  • Page 70 POWR Power unit 2. Wind the starter rope 1 2 times around NOTE: the sheave drum 3 in the direction of the Bend the outer end c of the spiral spring arrow shown in the illustration. onto the cutout d of the sheave drum. 5.

  • Page 71: Removing The Power Unit

    Power unit S69M5B90 NOTE: The starter rope 1 turns the sheave drum 3 with the force of the spiral spring. 8. Pull the manual starter handle 4 several times to check that the sheave drum turns smoothly and to check the starter rope for slack.
  • Page 72 POWR Power unit 2. Loosen the throttle cable stop screw 4 and remove the throttle cable 5. 3. Remove the carrying handle 6, fuel cock 7, bottom cowling 1 8, and bottom cowling 2 9. 4. Remove the power unit 0 by removing the bolts A.

  • Page 73: Cylinder Head

    Power unit / Cylinder head Cylinder head Part name Q’ty Remarks Cylinder head Gasket Not reusable Cylinder head cover Gasket Not reusable Intake valve Exhaust valve Push rod Push rod guide Stud bolt Rocker arm Rocker arm pivot Valve guide Not reusable Stem seal Not reusable...
  • Page 74 POWR Power unit Part name Q’ty Remarks M6 × 16 mm Bolt M6 × 45 mm Bolt Dowel Blowby hose 5-13 69M3E11...

  • Page 75: Removing The Cylinder Head

    Cylinder head Removing the cylinder head 1. Remove the cylinder head cover bolts in the sequence shown. S69M5290 NOTE: Insert a flat head screwdriver between the S69M5260 tab of the cylinder and the tab of the cylinder head to pry open the two parts. 2.

  • Page 76: Checking The Rocker Arms

    POWR Power unit 6. Remove the intake valve and exhaust Checking the push rod guide valve. 1. Check the push rod guide for cracks or damage. Replace if necessary. S69M5330 Checking the push rods 1. Check the push rods for bends, wear, or damage.

  • Page 77: Checking The Valves

    Cylinder head 2. Measure the valve spring tilt b. Replace Valve stem diameter b: if out of specification. Intake: 5.475–5.490 mm (0.2156–0.2161 in) Exhaust: 5.460–5.475 mm (0.2150–0.2156 in) 4. Measure the valve stem runout. Replace if out of specification. Valve spring tilt limit b: 1.2 mm (0.05 in) Checking the valves 1.

  • Page 78: Replacing The Valve Guides

    POWR Power unit 2. Calculate the valve stem-to-valve guide NOTE: clearance as follows. Replace the valve • Before installing the valve guide, mark its guide if out of specification. installation position b as shown. • Apply engine oil to the new valve guide. Valve stem-to-valve guide clearance = valve guide inside diameter –...

  • Page 79: Checking The Valve Seat

    Cylinder head Checking the valve seat 1. Eliminate carbon deposits from the valve with a scraper. 2. Apply a thin, even layer of Mechanic’s blueing dye (Dykem) onto the valve seat. 3. Lap the valve slowly on the valve seat with a valve lapper (commercially obtain- able) as shown.
  • Page 80 POWR Power unit 2. Cut the surface of the valve seat with a 45° cutter by turning the cutter clockwise until the valve seat face has become smooth. É 60˚ S69J5890 b Previous contact width 5. Use a 45° cutter to adjust the contact width of the valve seat to specification.

  • Page 81: Checking The Cylinder Head

    Cylinder head 7. If the valve seat contact area is too nar- CAUTION: row and situated near the top edge of the valve face, use a 30° cutter to cut the top Do not get the lapping compound on the edge of the valve seat.

  • Page 82: Installing The Valves

    POWR Power unit Installing the valves 3. Compress the valve spring, and then install the valve cotter 7 using a thin 1. Install the new stem seal 1 to the valve screwdriver with a small amount of guide. grease applied to it. S69M5440 S69M5460 2.

  • Page 83: Cylinder Block

    Cylinder head / Cylinder block Cylinder block Part name Q’ty Remarks Cylinder body Crankcase Crankshaft Camshaft Connecting rod assembly Piston Oil ring Second ring Top ring Piston pin Gasket Not reusable Oil splasher gear Oil seal housing Oil seal Not reusable Ball bearing Not reusable Oil seal...
  • Page 84 POWR Power unit Part name Q’ty Remarks Clamp Washer Dowel M8 × 20 mm Drain bolt M6 × 45 mm Bolt M8 × 14 mm Bolt M8 × 20 mm Bolt M6 × 29 mm Bolt M6 × 12 mm Bolt Piston pin clip Not reusable...

  • Page 85: Disassembling The Cylinder Body

    Cylinder block Disassembling the cylinder body 4. Remove the connecting rod bolts and the connecting rod cap, and then remove the 1. Remove the crankcase cover bolts in the connecting rod and piston assembly. sequence shown. 5. Remove the clips 3 with pliers, and then remove the piston.

  • Page 86: Checking The Cylinder Bore

    POWR Power unit Checking the cylinder bore Piston clearance: 1. Measure the cylinder bore (D 0.035–0.065 mm ) at measuring points a, b, (0.0014–0.0026 in) and c, and in direction d (D which is parallel to the crankshaft, and direction e (D Checking the piston rings ), which is at a right angle to the crankshaft.

  • Page 87: Checking The Piston Ring Grooves

    Cylinder block Checking the piston ring side clearance 1. Measure the piston ring side clearance. Replace the piston and piston rings as a set if out of specification. S69M5580 Piston ring end gap d: Top ring: Piston ring side clearance: 0.15–0.30 mm Top ring a: (0.0059–0.0118 in)

  • Page 88: Checking The Piston Pin

    POWR Power unit Checking the piston pin 1. Measure piston diameter. Replace if out of specification. S69M5660 Piston pin diameter: Connecting rod big end side 11.996–12.000 mm clearance a: (0.4723–0.4724 in) 0.2–0.6 mm (0.008–0.024 in) Checking the connecting rod small Checking the crankshaft end inside diameter 1.

  • Page 89: Checking The Crankpin Oil Clearance

    Cylinder block S69M5690 NOTE: Crankpin diameter a: Be sure not to put the Plastigauge (PG-1) 23.969–23.984 mm over the oil hole in the crankpin of the crank- (0.9437–0.9443 in) shaft. Crankpin width b: 21.0–21.1 mm (0.827–0.831 in) 3. Install the connecting rod to the crankpin 3.

  • Page 90: Checking The Camshaft

    POWR Power unit 4. Tighten the connecting rod bolts 2 to the specified torques in two stages. S69M5710 2. Check the decompressor for damage or S69M5640 wear. Replace the camshaft if necessary. NOTE: • Reuse the removed connecting rod bolts when checking the oil clearance.

  • Page 91: Checking The Valve Lifters

    Cylinder block 4. Measure the camshaft runout. Replace if out of specification. S69M5755 NOTE: S69M5730 Do not remove the ball bearing if not replac- ing it. Camshaft runout limit: 0.03 mm (0.0012 in) 2. Remove the ball bearing. Checking the valve lifters 1.

  • Page 92: Assembling The Cylinder Block

    POWR Power unit Assembling the cylinder block Disassembling the crankcase 1. Apply grease to the new oil seal, and 1. Remove the bolt and oil seal housing. then install it into the cylinder block. S69M5830 S69M5800 NOTE: Insert a flat head screwdriver between the Driver rod L3 1: 90890-06652 tab of the oil seal housing and the tab of the Needle bearing attachment 2:...

  • Page 93: Checking The Oil Seal Housing

    Cylinder block Checking the oil seal housing 3. Install the new O-ring. 1. Check the oil seal housing for cracks, damage, or corrosion. Replace if neces- sary. S69M5910 4. Install the oil seal housing 5 to the crankcase 6. S69M5860 Assembling the crankcase 1.

  • Page 94: Assembling The Piston And Cylinder Block

    POWR Power unit Assembling the piston and cylinder CAUTION: block Do not scratch the piston or break the pis- 1. Assemble the piston 1, connecting rod 2, piston pin 3, and new piston pin clips ton rings. NOTE: After installing the piston rings, check them for smooth operation.
  • Page 95 Cylinder block 6. Install the connecting rod cap A to the 8. Set the camshaft C into the cylinder connecting rod, and then tighten the con- block as shown. necting rod bolts to the specified torques in two stages. S69M5A00 NOTE: S69M5980 Align the crankshaft mark f and the cam-...
  • Page 96 POWR Power unit 11. Install the new gasket and cylinder head, and then tighten the cylinder head bolts H to the specified torques in two stages and in the sequence shown. S69M5A20 Crankcase bolt: 1st: 5 N·m (0.5 kgf·m, 3.7 ft·lb) 2nd: 11 N·m (1.1 kgf·m, 8.1 ft·lb) S69M5C10 CAUTION:...

  • Page 97: Installing The Power Unit

    Cylinder block Thermostat cover bolt N: 8 N·m (0.8 kgf·m, 5.9 ft·lb) Installing the power unit 1. Clean the power unit mating surfaces, and then install the dowels 1 and the new gasket 2. 2. Install the power unit 3 by installing the bolts 4, and then tighten them to the specified torque.
  • Page 98 POWR Power unit 5. Install the flywheel magnet 9 and starter pulley 0, and then tighten the flywheel magnet nut to the specified torque. S69M5A80 CAUTION: Apply force in the direction of the arrows shown, to prevent the flywheel holder from slipping off easily.

  • Page 99: Lowr

    LOWR Lower unit Special service tools ..................6-1 Lower unit ....................... 6-2 Removing the lower unit ................6-5 Removing the water pump and shift rod............ 6-5 Checking the water pump and shift rod .............6-6 Propeller shaft housing ................. 6-7 Removing the propeller shaft housing assembly........6-8 Disassembling the propeller shaft assembly ..........6-8 Disassembling the propeller shaft housing..........

  • Page 100: Lower Unit

    LOWR Lower unit Special service tools Bushing attachment Stopper guide stand 90890-06649, 90890-06650 90890-06538 Driver rod L3 Bearing puller claw 2 90890-06652 90890-06537 Needle bearing attachment Ball bearing attachment 90890-06615, 90890-06617 90890-06637, 90890-06638 Bearing puller Driver rod LS 90890-06535 90890-06606 Stopper guide plate 90890-06501 69M3E11...

  • Page 101: Lower Unit

    Special service tools / Lower unit Lower unit Part name Q’ty Remarks Lower unit Cotter pin Not reusable Propeller nut Washer Propeller Spacer Anode Lock washer M6 × 20 mm Bolt Gasket Not reusable Drain screw Washer L-transom model M6 × 155 mm / L-transom model Bolt M6 ×...
  • Page 102 LOWR Lower unit Part name Q’ty Remarks Rubber seal Extension L-transom model Dowel L-transom model Bushing L-transom model Circlip L-transom model Joint Joint M6 × 20 mm Bolt Cover 69M3E11...
  • Page 103 Lower unit S69M6020 Part name Q’ty Remarks M6 × 40 mm Bolt Plate Water pump housing O-ring Not reusable Insert cartridge Impeller Outer plate cartridge Dowel O-ring Not reusable Plate Gasket Not reusable Shift rod S- and L-transom models Dowel Dowel 69M3E11...

  • Page 104: Removing The Lower Unit

    LOWR Lower unit Removing the lower unit 1. Drain the gear oil. For draining proce- dures, see Chapter 3, “Changing the gear oil.” 2. Set the gear shift to the neutral position, and place a block of wood between the anti-cavitation plate and propeller to keep the propeller from turning, and then remove the propeller nut and propeller.

  • Page 105: Checking The Water Pump And Shift Rod

    Lower unit Checking the water pump and shift 4. Check the shift rod for cracks or wear. Replace if necessary. 1. Check the water pump housing for defor- mation. Replace if necessary. S69M6100 S69M6070 2. Check the impeller 1 and insert car- tridge 2 for cracks or wear.

  • Page 106: Propeller Shaft Housing

    LOWR Lower unit Propeller shaft housing Part name Q’ty Remarks Shift plunger Spring Propeller shaft Dog clutch Washer O-ring Not reusable Propeller shaft housing Bushing Oil seal Not reusable M6 × 16 mm Bolt 69M3E11...

  • Page 107: Removing The Propeller Shaft Housing Assembly

    Propeller shaft housing Removing the propeller shaft housing assembly 1. Remove the bolts 1, and then pull out the propeller shaft housing assembly 2. 2. Remove the bushing 2. NOTE: Insert a flat head screwdriver 3 into the slit between the sealing surfaces of the lower case to pry open the two parts.

  • Page 108: Checking The Propeller Shaft

    LOWR Lower unit Checking the propeller shaft Assembling the propeller shaft 1. Check the propeller shaft for bends or housing 1. Install the bushing 1 into the propeller wear. Replace if necessary. shaft housing. 2. Check the dog clutch, shift plunger, and NOTE: spring for cracks or wear.

  • Page 109: Drive Shaft And Lower Case

    Propeller shaft housing / Drive shaft and lower case Drive shaft and lower case Part name Q’ty Remarks Drive shaft S- and L-transom models Oil seal Not reusable Bushing 2 Not reusable Bushing 1 Not reusable Washer Pinion Circlip Ball bearing Not reusable Forward gear Circlip...

  • Page 110: Removing The Drive Shaft

    LOWR Lower unit Removing the drive shaft Bearing puller 1: 90890-06535 1. Remove the circlip 1, pinion, washer Stopper guide plate 2: 90890-06501 and drive shaft, and then pull out the for- Stopper guide stand 3: ward gear. 90890-06538 Bearing puller claw 2 4: 90890-06537 3.

  • Page 111: Checking The Pinion And Forward Gear

    Drive shaft and lower case 5. Use a bolt a with the specified measure- Checking the lower case ments, two nuts, and a plate as shown in 1. Check the skeg and torpedo for cracks or the illustration. damage. Replace if necessary. 6.

  • Page 112: Installing The Drive Shaft

    LOWR Lower unit 3. Install bushing 2 into the lower case to the specified depth. S69M6320 NOTE: S69M6350 Apply engine oil to bushing 1, 2 before instal- lation. CAUTION: Do not reuse the bearing, always replace it with a new one. Bushing attachment 1: 90890-06649 Driver rod L3 2: 90890-06652...

  • Page 113: Installing The Propeller Shaft Housing

    Drive shaft and lower case NOTE: If replacing the washer 1, be sure to replace it with a new one of the same thickness. Available washer thicknesses: 2.0, 2.1, 2.2, and 2.3 mm Installing the propeller shaft housing 1. Install the washer 1 and propeller shaft assembly 2 into the propeller shaft housing assembly 3.

  • Page 114: Installing The Lower Unit

    LOWR Lower unit 5. Install the new O-ring 9 and insert car- tridge 0 into the water pump housing A. S69M6400 NOTE: Align the insert cartridge projection b with the hole c in the water pump housing. 6. Install the water pump housing assembly B to the lower case.
  • Page 115 Drive shaft and lower case 3. Install the shift rod 1 to the joint 2, and then tighten the bolt 3 to the specified WARNING torque. • Do not hold the propeller with your hands when loosening or tightening it. •...
  • Page 116 LOWR Lower unit — MEMO — 6-17 69M3E11...

  • Page 117: Brkt

    BRKT Bracket unit Tiller handle ....................7-1 Assembling the tiller handle............... 7-3 Installing the tiller handle ................7-3 Upper case, swivel bracket, and clamp brackets........7-4 Assembling the swivel bracket ..............7-8 Assembling the clamp brackets..............7-9 Installing the upper case................7-9 69M3E11...

  • Page 118: Tiller Handle

    BRKT Bracket unit Tiller handle · · · 26 N m (2.6 kgf m, 19.2 ft S69M7010 Part name Q’ty Remarks Tiller handle Throttle grip ø5 × 21 mm Screw Throttle friction adjuster Engine shut-off switch Engine shut-off cord Throttle lever Bushing Spring Washer...
  • Page 119 Tiller handle · · · 26 N m (2.6 kgf m, 19.2 ft S69M7010 Part name Q’ty Remarks Bushing ø5 × 7 mm Screw Cover Throttle cable Washer Bushing Cover M8 × 25 mm Bolt 69M3E11...

  • Page 120: Assembling The Tiller Handle

    BRKT Bracket unit Assembling the tiller handle 3. Install the tiller handle assembly to the upper case, and then tighten the bolt 3 1. Install the throttle cable 1 to the throttle lever 2. to the specified torque. S69M7020 NOTE: Make sure that the throttle grip is fully closed when installing the throttle cable.
  • Page 121 Tiller handle / Upper case, swivel bracket, and clamp brackets Upper case, swivel bracket, and clamp brackets · · · m (0.5 kgf m, 3.7 ft · · · m (0.3 kgf m, 2.2 ft · · · 12 N m (1.2 kgf m, 8.9 ft S69M7050...
  • Page 122 BRKT Bracket unit · · · m (0.5 kgf m, 3.7 ft · · · m (0.3 kgf m, 2.2 ft · · · 12 N m (1.2 kgf m, 8.9 ft S69M7050 Part name Q’ty Remarks Bushing Friction piece Swivel bracket M6 ×...

  • Page 123: Upper Case, Swivel Bracket, And Clamp Brackets

    Upper case, swivel bracket, and clamp brackets · · · 16 N m (1.6 kgf m, 11.8 ft · · · m (0.5 kgf m, 3.7 ft 13 12 · · · m (0.5 kgf m, 3.7 ft S69M7060 Part name Q’ty Remarks Port clamp bracket...
  • Page 124 BRKT Bracket unit · · · 16 N m (1.6 kgf m, 11.8 ft · · · m (0.5 kgf m, 3.7 ft 13 12 · · · m (0.5 kgf m, 3.7 ft S69M7060 Part name Q’ty Remarks Lever Tilt stop lever 2 Spring Bushing...

  • Page 125: Assembling The Swivel Bracket

    Upper case, swivel bracket, and clamp brackets Assembling the swivel bracket 1. Install the bushing 1 into the swivel bracket 2, and then insert tilt stop lever 1 3 partially into the swivel bracket 2. 2. Hook the spring 4 onto tilt stop lever 1 S69M7090 9.

  • Page 126: Assembling The Clamp Brackets

    BRKT Bracket unit Assembling the clamp brackets Swivel bracket bolt 1: 1. Install the swivel bracket and mount housing between the clamp brackets, 12 N·m (1.2 kgf·m, 8.9 ft·lb) and then tighten the nuts to the specified torques. 2. Install the cover 2 to the swivel bracket. 3.

  • Page 127: Elec

    – ELEC Electrical systems Special service tools ..................8-1 Electrical components................... 8-2 Top view ....................8-2 Wiring harness................... 8-3 Ignition system....................8-4 Checking the ignition spark gap ..............8-4 Checking the spark plug cap ..............8-4 Checking the TCI unit ................8-5 Checking the engine shut-off switch............

  • Page 128: Special Service Tools

    – ELEC Electrical systems Special service tools Ignition tester 90890-06754 Digital circuit tester 90890-03174 69M3E11...

  • Page 129: Electrical Components

    Special service tools / Electrical components Electrical components Top view S69M8010 1 Spark plug cap 2 Spark plug wire 3 TCI unit 4 Engine shut-off switch 69M3E11...

  • Page 130: Wiring Harness

    – ELEC Electrical systems Wiring harness 1 Flywheel magnet : Black 2 TCI unit : White 3 Engine shut-off switch 4 Ground 5 Spark plug 69M3E11...

  • Page 131: Ignition System

    Electrical components / Ignition system Ignition system Checking the ignition spark gap 1. Disconnect the spark plug cap 1 from the spark plug. 2. Connect the special service tool to the spark plug cap and to the ground bolt. S69M8060 WARNING •...

  • Page 132: Checking The Tci Unit

    – ELEC Electrical systems Checking the TCI unit 1. Remove the spark plug cap from the spark plug wire by turning the cap coun- terclockwise. 2. Measure unit resistance. Replace if out of specification. Lead color White (W) Black (B) Clip removed a Clip installed b Engine stop button...

  • Page 133: Trbl Shtg

    TRBL SHTG Troubleshooting Power unit....................... 9-1 69M3E11...
  • Page 134 TRBL SHTG Troubleshooting NOTE: • To diagnose a mechanical malfunction, use the troubleshooting charts pertaining to the trouble located in this chapter. Also, when checking and maintaining the outboard motor, see Chapters 4– 8 for safe maintenance procedures. • Check that all electrical connections are tight and free from corrosion. Power unit Symptom: Engine does not start (manual starter is operating normally).
  • Page 135 Power unit Clean, adjust or replace the Good condition? spark plug. Check the compression pres- sure of the combustion chamber. Out of Check the fuel system. specification? Check the valve clearance. Out of Adjust the valve clearance. specification? Check the cylinder head, cylin- der body, and piston assembly.
  • Page 136 TRBL SHTG Troubleshooting Symptom: Engine can be started, but does not remain on. • Check the fuel system. • Check the ignition system. • Check the compression pressure of the power unit. Fuel system Check that the air vent screw of the fuel tank is open. Is the vent Open the air vent screw.
  • Page 137 Power unit Compression pressure Check that there is no secondary air intake on the contact surfaces of the carburetor. Is there air Replace the respective seals. intake? Check the compression pres- sure of the combustion chamber. Symptom: The engine idle speed is not steady, but increases or decreases. •...
  • Page 138 TRBL SHTG Troubleshooting Symptom: Engine does not accelerate when the throttle is opened quickly. The engine turns off when the throttle is opened quickly. Acceleration is tardy and the engine is likely to stop at any moment. • Check the carburetors. •...
  • Page 139 Power unit Symptom: Shift mechanism of the forward gear does not operate properly. Check the operation of the shift lever. Good operat- Check the bracket, spring, and ing condition? ball. Check the condition of the shift rod connection. Connected Replace the shift rod. properly? Disassemble the lower case, and then check the operation of...
  • Page 140 Index Checking the fuel system ......1-15 Checking the fuel tank and Adjusting the engine idle speed ....1-18 fuel filler cap ..........4-7 Adjusting the pilot screw ......4-10 Checking the gear oil........ 1-15 After test run ..........1-18 Checking the gear oil level ......3-9 Applicable model.........1-5 Checking the gear shift and Assembling the carburetor ......4-9...
  • Page 141 Index Dimensions ..........2-6 Low vibration tiller handle ......1-11 Disassembling the crankcase ....5-31 Lower unit ..........3-9 Disassembling the cylinder block....5-30 Lubricating the outboard motor....3-12 Disassembling the cylinder body ....5-24 Disassembling the lower case ....6-11 Disassembling the manual starter....5-7 Maintenance interval chart ......3-2 Disassembling the propeller shaft Maintenance specifications ......
  • Page 142 Index Upper case, swivel bracket, and clamp brackets..........7-4 Ventilation ...........1-3 Wiring harness ..........8-3 69M3E11...
  • Page 144 YAMAHA MOTOR CO., LTD. Printed in the Netherlands May 2002 – 1.3 × 1 CR...

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