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F25
T25
SERVICE MANUAL
LIT-18616-03-17
6BP-28197-1M-11

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Summary of Contents for Yamaha F25

  • Page 1 SERVICE MANUAL LIT-18616-03-17 6BP-28197-1M-11...
  • Page 2 Contents General information INFO Specification SPEC TECH Technical features and description Rigging information GING TRBL Troubleshooting SHTG Electrical system ELEC Fuel system FUEL Power unit POWR Lower unit LOWR Bracket unit BRKT Maintenance Index Appendix...
  • Page 3: Table Of Contents

    INFO General information Safety while working ............0-1 Rotating part................0-1 Hot part..................0-1 Electric shock ................0-1 Propeller ..................0-1 Handling of gasoline..............0-1 Ventilation................... 0-1 Self-protection ................0-2 Working with crane..............0-2 Handling of gas torch ..............0-2 Part, lubricant, and sealant............
  • Page 4: Safety While Working

    INFO General information Safety while working Handling of gasoline • Gasoline is highly flammable. Keep gaso- To prevent an accident or injury and to pro- line and all flammable products away from vide quality service, observe the following heat, sparks, and open flames. safety procedures.
  • Page 5: Self-Protection

    Yamaha, when servicing or repairing the out- • If the outboard motor does not have three board motor. or more points to be suspended, support it...
  • Page 6: Special Service Tool

    INFO General information Special service tool Disassembly and assembly Use the recommended special service tools • Use compressed air to remove dust and dirt to work safely, and to protect parts from dam- during disassembly. age. • Apply engine oil to the contact surfaces of moving parts before assembly.
  • Page 7: Abbreviation

    INFO General information Abbreviation The following abbreviations are used in this service manual. Abbreviation Description ABYC American Boat and Yacht Council American Petroleum Institute ATDC After Top Dead Center BTDC Before Top Dead Center CARB California Air Resources Board Cold Cranking Ampere Capacitor Discharge Ignition Centerline Exhaust...
  • Page 8: Lubricant, Sealant, And Thread Locking Agent

    Lubricant, sealant, and thread locking agent Symbol Symbols in an exploded diagram or illustration indicate the grade of lubricant and the lubrication points. Symbol Name Application Yamaha 4-stroke motor oil Lubricant Gear oil Lubricant Water resistant grease Lubricant (Yamaha grease A)
  • Page 9: Special Service Tool

    Sealant Special service tool For U.S.A. and Canada Special service tools with part numbers “YB-*****” are distributed by K & L. Special service tools with Yamaha part numbers (90890-*****) are distributed by the Parts Division. Drilling plate Spark checker 90890-06783...
  • Page 10 Lubricant, sealant, and thread locking agent / Special service tool Pressure/vacuum tester Valve spring compressor YB-35956-A YM-04019 Compression gauge Valve attachment YU-33223 YB-06320 Flywheel magnet holder Valve guide remover YB-06139 YB-06801 Universal puller Valve guide reamer YB-06117 YM-01196 Crankshaft holder Valve lapping tool YW-06355 YM-A8998...
  • Page 11 INFO General information Neway valve seat kit Propeller shaft needle bearing attachment YB-91044 YB-06153 Driver handle (large) Driver handle (small) YB-06071 YB-06229 Driveshaft outer race installer Bearing housing/driveshaft bearing YB-06110 remover/installer YB-06082 Piston ring compressor YM-08037 Driveshaft needle bearing installer and remover YB-06196 Slide hammer...
  • Page 12 Special service tool Forward gear outer race installer Oil seal installer YB-06085 YB-06023 Driveshaft holder Bearing cup installer YB-06079 YB-06167 Pinion nut wrench Bearing inner race attachment YB-06078 90890-06644 Oil seal installer Bearing inner race attachment YB-06168 90890-06645 Bearing splitter plate Pinion shim selecting tool YB-06219 YB-34432-10, YB-34432-11A, YB-34432-16,...
  • Page 13 INFO General information Forward gear shim gauge Backlash adjustment plate YB-06344 YB-07003 Reverse gear shim gauge Magnetic base stand YB-39799 YU-A8438 Bearing housing puller Pinion height gauge YB-06234 90890-06668 Backlash indicator rod Bearing puller legs YB-06265 YB-06523 Dial indicator gauge Bearing housing bearing/oil seal remover YU-03097 YB-06112...
  • Page 14 Special service tool Bearing housing bearing/oil seal installer Driveshaft outer race installer YB-06111 YB-06110 Driveshaft holder Forward gear bearing installer YB-06079 YB-06270-A Roller bearing installer/remover Bearing installer-reverse gear bearing YB-06432 YB-06016 Driveshaft needle bearing Bearing housing puller remover/installer YB-06207 YB-06063 Reverse gear bearing remover Forward gear outer race installer YB-41707...
  • Page 15 INFO General information Pinion gear bushing installer YB-06029-4 Crankshaft seal installer YB-06349 Driveshaft needle bearing installer and remover YB-06230 Trim/cylinder wrench YB-06175-2B Digital tachometer YU-39951-B 0-13...
  • Page 16 Special service tool — MEMO — 0-14...
  • Page 17 SPEC Specification Model features ................1-1 General feature ................1-1 Model designation ..............1-2 Serial number ................1-2 Model data ..................1-3 Dimension and Weight ............... 1-3 Performance................1-3 Power unit .................. 1-4 Bracket unit ................1-5 Lower unit................... 1-5 Fuel and oil requirement.............
  • Page 18 Special tightening torque ............1-20 Rigging information ..............1-20 Fuel system ................1-20 Power unit ................1-21 Lower unit................. 1-22 Bracket unit ................1-22 PTT unit..................1-23 Optional equipment ..............1-23 General tightening torque ............1-23...
  • Page 19: Model Features

    SPEC Specification Model features General feature F25 and T25 Overall Features • Single carburetor with accelerator pump • 4-stroke, L2, SOHC, 4-valve, 498.0 cm (30.4 cu. in) engine • Low emission in compliance with US EPA and US CARB 3-STAR emission standards a Power unit •...
  • Page 20: Model Designation

    A: A and up Serial number The outboard motor serial number is indi- cated on a label affixed to the port clamp bracket. YAMAHA MOTOR CO., LTD. MADE IN JAPAN PAYS D'ORIGINE JAPON 1 Model name 2 Approved model code...
  • Page 21: Model Data

    SPEC Specification Model data Dimension and Weight Model Item Unit F25MHA F25EHA Overall length mm (in) 1181.0 (46.5) Overall width mm (in) 412.0 (16.2) Overall height mm (in) 1157.0 (45.6) mm (in) 1284.0 (50.6) Boat transom height mm (in) 381.0 (15.0) mm (in) 508.0 (20.0) Weight (with AL propeller)
  • Page 22: Power Unit

    Model data Model Item Unit F25EA F25A T25A Maximum output at 5500 r/min kW (HP) 19.3 (25) Full throttle operating range r/min 5000–6000 Maximum fuel consumption L (US gal, at 5500 r/min 9.2 (2.4, 2.0) Imp gal)/hr Engine idle speed r/min 925–1025 Power unit...
  • Page 23: Bracket Unit

    SPEC Specification Model Item Unit F25EA F25A T25A Exhaust system Propeller boss Lubrication system Wet sump Bracket unit Model Item Unit F25MHA F25EHA Trim angle (at 12° boat transom) Degree –4, 0, 8, 12 Tilt-up angle Degree Steering angle Degree 42 + 42 Trim and tilt system Manual...
  • Page 24: Fuel And Oil Requirement

    Model data Fuel and oil requirement Model Item Unit F25MHA F25EHA Fuel type Regular unleaded gasoline Fuel minimum rating YAMALUBE 4-M FC-W oil or 4-stroke motor Engine oil oil with combinations of the following SAE and API oil classifications Engine oil grade (*1) SE, SF, SG, SH, SJ, SL 5W-30, 10W-30, 10W-40 Total engine oil quantity...
  • Page 25: Battery Requirement

    SPEC Specification Battery requirement Model Item Unit F25MHA F25EHA Minimum cold cranking amps CCA/SAE — 245.0 Minimum rated capacity MCA/ABYC — 323.0 Minimum reserve capacity RC/SAE Minutes — Model Item Unit F25EA F25A T25A Minimum cold cranking amps CCA/SAE 245.0 Minimum rated capacity MCA/ABYC 323.0...
  • Page 26 Model data / Electrical technical data Model Item Unit F25MHA F25EHA Neutral switch Input voltage (*1) 12.0 Thermo sensor Resistance (*1) at 75 °C (167 °F) kΩ 0.372 Charge coil Resistance (*1) Ω at 20 °C (68 °F) 28.9–39.1 Output peak voltage 70.0 at cranking (unloaded) at cranking (loaded)
  • Page 27: Engine Speed Control System

    SPEC Specification Model Item Unit F25EA F25A T25A Charge coil Resistance (*1) Ω at 20 °C (68 °F) 28.9–39.1 Output peak voltage at cranking (unloaded) 70.0 at cranking (loaded) 110.0 at 1500 r/min (loaded) 190.0 at 3500 r/min (loaded) 190.0 CDI unit Output peak voltage at cranking (loaded)
  • Page 28: Ptt System

    Electrical technical data Model Item Unit F25EA F25A T25A Power bobbin Output peak voltage at cranking (loaded) 10.6 at 1500 r/min (loaded) 25.1 at 3500 r/min (loaded) 59.1 (*1) The figures are for reference only. PTT system Model Item Unit F25EA F25A T25A...
  • Page 29: Starting System

    SPEC Specification Model Item Unit F25EA F25A T25A Rectifier Regulator Output peak voltage at 1500 r/min (loaded) 13.0 at 3500 r/min (loaded) 13.0 (*1) The figures are for reference only. Starting system Model Item Unit F25MHA F25EHA Starter motor Type —...
  • Page 30: Fuel System Technical Data

    Electrical technical data / Fuel system technical data Fuel system technical data Fuel system Model Item Unit F25MHA F25EHA Fuel joint Holding pressure Positive pressure (kgf/cm 50.0 (0.50, 7.3) psi) Fuel filter assembly Holding pressure Positive pressure (kgf/cm 200.0 (2.00, 29.0) psi) Fuel pump Holding pressure...
  • Page 31: Power Unit Technical Data

    SPEC Specification Model Item Unit F25EA F25A T25A Fuel pump Holding pressure Inlet positive pressure (kgf/cm 50.0 (0.50, 7.3) psi) Inlet negative pressure (kgf/cm 30.0 (0.30, 4.4) psi) Outlet positive pressure (kgf/cm 50.0 (0.50, 7.3) psi) Carburetor 14.0 ± 2.0 (0.55 ± 0.08) Float height mm (in) Valve seat size...
  • Page 32: Manual Starter

    Fuel system technical data / Power unit technical data Model Item Unit F25EA F25A T25A Engine oil Oil pressure (*2) at 60 °C (140 °F) with SL 10W-30 engine oil and at (kgf/cm 250.0 (2.50, 36.3) 950 r/min psi) Thermostat Valve opening temperature °C (°F) 58.0–62.0 (136–144)
  • Page 33 SPEC Specification Model Item Unit F25MHA F25EHA Camshaft Cam lobe height Intake mm (in) 30.839–30.939 (1.2141–1.2181) Exhaust mm (in) 30.937–31.037 (1.2180–1.2219) Cam lobe width Intake and exhaust mm (in) 25.950–26.050 (1.0217–1.0256) Journal diameter #1 mm (in) 36.925–36.945 (1.4537–1.4545) Journal diameter #2 mm (in) 36.935–36.955 (1.4541–1.4549) Cylinder head journal inside...
  • Page 34 Power unit technical data Model Item Unit F25EA F25A T25A Valve spring Free length mm (in) 39.9 (1.57) Tilt mm (in) 1.7 (0.07) Camshaft Cam lobe height Intake mm (in) 30.839–30.939 (1.2141–1.2181) Exhaust mm (in) 30.937–31.037 (1.2180–1.2219) Cam lobe width Intake and exhaust mm (in) 25.950–26.050 (1.0217–1.0256)
  • Page 35: Crankcase Assembly

    SPEC Specification Crankcase assembly Model Item Unit F25MHA F25EHA Cylinder Bore mm (in) 65.000–65.015 (2.5591–2.5596) Piston Diameter mm (in) 64.950–64.965 (2.5571–2.5577) Measuring point mm (in) 5.0 (0.20) Piston clearance mm (in) 0.035–0.065 (0.0014–0.0026) Ring groove (Top) mm (in) 1.210–1.230 (0.0476–0.0484) Ring groove (2nd) mm (in) 1.510–1.530 (0.0594–0.0602)
  • Page 36 Power unit technical data Model Item Unit F25EA F25A T25A Cylinder Bore mm (in) 65.000–65.015 (2.5591–2.5596) Piston Diameter mm (in) 64.950–64.965 (2.5571–2.5577) Measuring point mm (in) 5.0 (0.20) Piston clearance mm (in) 0.035–0.065 (0.0014–0.0026) Ring groove (Top) mm (in) 1.210–1.230 (0.0476–0.0484) Ring groove (2nd) mm (in) 1.510–1.530 (0.0594–0.0602)
  • Page 37: Lower Unit Technical Data

    SPEC Specification Model Item Unit F25EA F25A T25A Crankcase Crankshaft journal oil mm (in) 0.012–0.036 (0.0005–0.0014) clearance (*1) The figures are for reference only. Lower unit technical data Lower unit assembly Model Item Unit F25MHA F25EHA Lower unit Holding pressure (kgf/cm 98.1 (0.981, 14.2) psi)
  • Page 38: Bracket Unit Technical Data

    Power unit technical data / Lower unit technical data / Bracket unit technical data / Special tightening torque Model Item Unit F25EA F25A T25A 0.10, 0.12, 0.7, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 0.15, 0.18, Pinion shim (T3) 0.30, 0.40, 0.50 0.10, 0.12, 0.15, 0.18,...
  • Page 39: Power Unit

    SPEC Specification Power unit Tightening torques Part to be tightened Screw size N·m kgf·m ft·lb Oil pressure switch — Pulser coil bolt Adjusting screw locknut — 10.3 Drive plate screw ø5 0.54 3.98 Cover screw ø4 0.15 1.11 Sheave drum screw ø5 0.34 2.51...
  • Page 40: Lower Unit

    Special tightening torque Lower unit Tightening torques Part to be tightened Screw size N·m kgf·m ft·lb Check screw — Drain screw — Lower case mounting bolt 27.3 Propeller nut — 25.1 Propeller shaft housing bolt Pinion nut — 36.9 Water inlet cover screw Lower case mounting bolt (high thrust model) 28.8 Propeller shaft housing bolt (high thrust model)
  • Page 41: Ptt Unit

    SPEC Specification PTT unit Tightening torques Part to be tightened Screw size N·m kgf·m ft·lb Stator screw Brush holder screw PTT motor assembly bolt Reservoir cap — Manual valve — Gear pump bolt Valve lock screw — Gear pump housing bolt Main valve —...
  • Page 42 TECH Technical features and description Engine control system .............. 2-1 Outline ..................2-1 Ignition control system ............. 2-3 Ignition timing control ..............2-3 Basic ignition timing control............2-4 Starting ignition timing control ............ 2-4 Acceleration ignition timing control..........2-5 Cold and warm engine ignition timing control......2-6 Engine speed control..............
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