TOHATSU MFS 6CZ Service Manual
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TOHATSU MFS 6CZ Service Manual

TOHATSU MFS 6CZ Service Manual

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S E R V I C E
M A N U A L
STROKE
MFS CZ
MFS C
MFS . C
MFS . CY
Models
- BD ｜
OB No.
-
-
NB

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Summary of Contents for TOHATSU MFS 6CZ

  • Page 1 S E R V I C E M A N U A L STROKE MFS CZ MFS C MFS . C MFS . CY Models - BD ｜ OB No.

  • Page 3: Before Reading This Manual

    Introduction Before reading this manual This service manual provides information that is needed for inspection, service and repair of applicable outboard motors. For information about operation of the products that are not described in this document, refer to the owners manual. For our customers' safe and dependable use of the product for long term, it is essential to maintain the performance and quality of the outboard.

  • Page 4: About This Manual

    About this manual Composition and use of this manual This service manual is designed so that service persons are able to perform repairs correctly. Understand the following matters well for efficient service and repair. Each chapter begins with the introduction of special tools that are used for the work described. Parts that are serviced in each chapter and their details are presented by using a component composition diagram.
  • Page 5 This manual uses SI unit system (International System of Units) for pressure, force (load), torque and stress. This manual newly adopts the international unit construction system (SI unit system) followed by the conventional imperial and metric systems enclosed by ( ) and [ ] as described below. Example : <Pressure>...
  • Page 6 Description of Pictograph The following symbols represent the contents of individual chapters. Service Inspections and Service Data Fuel System Information Adjustments (Fuel Injection) Electrical Power Unit Lower Unit Bracket System Wiring Troubleshooting Diagrams The following symbols indicate items needed for the service. Lubrication Tightening Special Tool...

  • Page 7: Table Of Contents

    1. Service Information 10) Inspection of Timing Belt ……………………… 3-12 11) Replacement of Timing Belt ………………… 3-13 1. Identification (Engine Serial Number) …… 1-2 12) Inspection of Spark Plugs ……………………… 3-18 2. Ensuring Work Safety ……………………… 1-2 13) Inspection of Compression Pressure …… 3-19 1) Fire Prevention………………………………………...
  • Page 8 2) Vapor Separator …………………………………… 4-26 30) Inspection of Piston Ring ……………………… 5-58 3) Fuel Regulator ……………………………………… 4-27 31) Inspection of Piston Pin ………………………… 5-59 4) Fuel Cooler …………………………………………… 4-27 32) Inspection of Connecting Rod Small End Inner Diameter ……………………………… 5-59 7.
  • Page 9 8. Electrical System 29) Backlash Measurement and Shim Selection … 6-24 30) Installation of Propeller Shaft Housing …… 6-26 1. Special Tools ………………………………… 8-2 31) Installation of Pump Case ……………………… 6-27 2. Electrical Component Layout …………… 8-3 32) Installation of Water Pump …………………… 6-27 Port Side View …………………………………………...
  • Page 10 State 3 Engine rotation is unstable or hunting occurs in low speed range. ……… 9-14 Ignition System ……………………………………… 9-15 Fuel System ………………………………………… 9-16 PT Unit ………………………………………………………… 9-17 State 1 PT unit will not operate. ………… 9-17 State 2 PT unit is not capable of sustaining the outboard motor.
  • Page 11 INDEX Service Information Service Data Maintenance Fuel System (Fuel Injection) Power Unit Lower Unit Bracket Electrical System Troubleshooting Wiring Diagram 4st 6/8/9.9 2024...
  • Page 12 4st 6/8/9.9 2024...
  • Page 13 Service Information 1. Identification (Engine Serial Number) …… 1-2 2) Gear Shift …………………………………………… 1-8 2. Ensuring Work Safety ……………………… 1-2 3) Engine Oil …………………………………………… 1-9 1) Fire Prevention……………………………………… 1-2 4) Gear Oil ………………………………………………… 1-9 2) Ventilation …………………………………………… 1-2 5) Fuel Line ……………………………………………… 1-9 3) Protection ……………………………………………...

  • Page 14: Service Information

    Service Information 1. Identification (Engine Serial Number) The engine serial number is stamped on the swivel bracket of the outboard motor body. 1 Model Name 2 Serial Number A Tiller Handle Model B Remote Control Model C Power Tilt Model 2.

  • Page 15: Protection

    3) Protection Wear a pair of goggles, working gloves and safety shoes to protect human body from chemicals and oils and eyes from particles generated by grinding or polishing works. 4) Genuine Parts Us e p ar t s an d /or c h e mi c als th a t ar e g e nuin e or recommended.

  • Page 16: Cautions In Disassembling And Assembling Components

    Service Information 7) Cautions in disassembling and assembling components (1) Install the outboard motor securely to a dedicated stand. (2) Take special care not to scratch the painted surfaces or mating surfaces of the cylinder block and crankcase. (3) Replace parts that cannot be reused such as packings, gaskets, O-rings, oil seals, spring pins or split pins with new ones after disassembly.

  • Page 17: Tools And Instruments

    3. Tools and Instruments 1) Test Propeller MFS6CZ MFS8C MFS9.8C Part No. 3B2-64110-1 3B2-64110-1 3B2-64110-1 Outer Diameter a 164 mm (6.46 in) 164 mm (6.46 in) 164 mm (6.46 in) Width b 12 mm (0.47 in) 12 mm (0.47 in) 12 mm (0.47 in) Fully Open 4500 to 5000 min...

  • Page 18: Special Tools

    Service Information 3) Special Tools Spring Pin Tool A (ø3.0) Spring Pin Tool B (ø3.0) Spring Pin Tool A (ø3.5) Spring Pin Tool B (ø3.5) P/N. 345-72227-0 P/N. 345-72228-0 P/N. 369-72227-0 P/N. 369-72228-0 Removing spring pin Installing spring pin Removing spring pin Installing spring pin Tachometer Vacuum/Pressure Gauge...
  • Page 19 Bearing Outer Press Kit Backlash Measuring Tool Kit Spark Tester Valve Spring Compressor Attachment P/N. 3B7-72739-1 P/N. 369-72740-0 P/N. 3F3-72540-0 P/N. 3AB-99076-0 Bevel Gear Assy A Measuring between bevel gear Installing and removing valve Inspecting ignition Installing bearing outer race assy A and bevel gear B spring Thickness Gauge...

  • Page 20: Pre-Delivery Inspection

    Service Information 4. Pre-delivery Inspection 1) Steering Handle A Check installations for clattering and play → B Adjust steering friction → C Check throttle grip for movement (full open/full close) → Adjust throttle friction → 2) Gear Shift Check that gear shifts from neutral (N) to forward (F) and reverse (R) smoothly.

  • Page 21: Engine Oil

    3) Engine Oil CAUTION Engine oil is removed before shipment to prevent leakage. Fill the engine with engine oil. 4 Stroke Engine Oil: 800 mL (0.8 US qt.) a Upper Limit Use oil level gauge to check oil quantity. b Lower Limit 4) Gear Oil Check the quantity of gear oil.

  • Page 22: Inspection Of Manual Tilt (Mf, Ef, Ep)

    Service Information 7) Inspection of Manual Tilt (MF, EF, EP) 1. Check that the outboard motor tilts up/down smoothly. 2. Fully tilt up the outboard motor to check that the tilt limit mechanism engages automatically. 8) Inspection of PT unit (EFT, EPT) 1.
  • Page 23 3. Press the stop switch 3 hard or pull out the lock 4 from the stop switch to check that the engine stops. A Tiller Handle Model B Remote Control Model 4st 6/8/9.9 2024 1-11...

  • Page 24: Cooling Water Check Port

    Service Information 10) Cooling Water Check Port Check that water is discharged from the cooling water check port 1 . 11) Idling After the engine has warmed up, use a tachometer to check that the idle revolution speed is as specified. Idle Revolution Speed: 900 min (rpm)

  • Page 25: Trim Tab

    Propeller List (No. of Blades x Pitch x Diameter) Propeller Mark Part No. 4×5.0×8.7 4×127×221 3V1B64510-1 4×7.0×8.7 4×178×226 3V1B64514-1 3×6.5×8.5 3×165×216 3B2B64513-1 3×7.0×8.9 3×178×226 3B2B64514-1 3×7.5×8.5 3×190×216 3B2B64515-1 F8.5 3×8.3×8.9 3×211×226 3B2B64517-1 F9.5 3×10×8.9 3×255×226 3B2B64519-1 13) Trim Tab Trim Tab Angle Adjustment After installing the outboard motor on your boat, make sure the weight of the left and right steering handle is evenly distributed at the trim angle and engine speed that you...

  • Page 26: Break-In Operation

    Service Information 5. Break-in Operation Bre ak - in op eration is ne e de d for the purp ose of smoothening the sliding surfaces between components such as pistons and cylinder, piston rings, piston pins, crankshaft, connecting rods, and intake and exhaust valves. •...

  • Page 27: Checks After Test Run

    4. Run at 3,000 min (rpm) or half of the WOT for an initial 2 hours, then at 4,000 min (rpm) or 3/4 of the WOT for 1 hour. 5. Check that the outboard motor is not tilted up and that water does not infiltrate the boat when the gear is shifted to the Reverse (R) position.
  • Page 28 Service Information 1-16 4st 6/8/9.9 2024...

  • Page 29: Service Data

    Service Data 1. Outline Dimensions ………………………… 2-2 4. Cooling Water System Diagram …………… 2-8 1) Engine Dimensions ………………………………… 2-2 5. Specifications ………………………………… 2-9 2) Transom Bolts ……………………………………… 2-4 6. Maintenance Data …………………………… 2-12 2. Fuel Injection System ……………………… 2-6 7. Tightening Torque Data ……………………… 2-20 1) ECU Fuel Feed System …………………………...

  • Page 30: Outline Dimensions

    Service Data 1. Outline Dimensions 1) Engine Dimensions Basic Tiller Handle Model EP model EPT model 4st 6/8/9.9 2024...
  • Page 31 MF/EF/EFT EP/EPT MFS6/8/9.8/9.9C MFS6/8/9.8/9.9C Item Type Unit Item Type Unit mm/in 15.15 mm/in 15.15 mm/in 26.60 mm/in 26.60 mm/in 31.60 mm/in 31.60 mm/in 36.60 mm/in 36.60 mm/in 17.05 mm/in 17.05 mm/in 22.05 mm/in 22.05 mm/in 27.05 mm/in 27.05 MF/EF mm/in 23.15 mm/in 22.45...

  • Page 32: Transom Bolts

    Service Data 2) Transom Bolts Manual Tilt Model (MF/EF) CENTER LINE 90mm 87mm (3.54in) (3.43in) TOP OF TRANSOM 58mm 58mm (2.28in) (2.28in) 86mm 83mm (3.39in) (3.27in) Allowable Transom Thikness 30~55mm(1.18~2.17in) Manual Tilt Model (EP) CENTER LINE 93.5mm 93.5mm (3.68in) (3.68in) TOP OF TRANSOM 76.5mm 76.5mm...
  • Page 33 Power Tilt Model (EFT/EPT) CENTER LINE 76.6mm 76.6mm TOP OF (3.00in) (3.00in) TRANSOM 97.5mm 97.5mm (3.83in) (3.83in) 94.2mm 94.2mm (3.70in) (3.70in) 97mm 97mm (3.81in) (3.81in) 10mm (0.39in) 4st 6/8/9.9 2024...

  • Page 34: Fuel Injection System

    Service Data 2. Fuel Injection System 1) ECU Fuel Feed System The ECU uses various sensors to precisely control the injected fuel amount (time) and ignition timing. Alternator Fuel Feed Pump (Exciter Coil) (FFP) Fuel Control Pulser Coil Fuel Injector (Crank Position Sensor) Idle MAP(Intake pressure) (Idle Speed Control Valve) Air Control Sensor Electric Ignition...

  • Page 35: Engine Lubrication System Diagram

    3. Engine Lubrication System Diagram Crankshaft Oil pressure switch upper bearing No.1 cylinder wall Cam shaft upper journal No.1 No.1 crank pin piston No.1 piston pin Rocker arm shaft Cam face rocker arm/valve No.2 cylinder wall No.2 No.2 crank pin piston No.2 piston pin...

  • Page 36: Cooling Water System Diagram

    Service Data 4. Cooling Water System Diagram Thermostat Cylinder Head Cylinder Vapor Separator Fuel Pump Cooling Water  Intake Cooling Water  Pump Cooling Water  Pipe Cooling Water Check Port Lower Part of  Cylinder (Water supply  Vapor Separator passages Idle Port in the drive shaft  housing) Cooling Water  Pipe Drive Shaft Housing Cylinder Cylinder Head Themostat Cooling Water  Lower Part of  Pump Cylinder Exhaust Gas &  Idle Port Drainage (Water supply ...

  • Page 37: Specifications

    5. Specifications Model Item Unit Dimensions Overall Length mm (in) 977 (38.45) 596 (23.45) 607 (23.90) Overall Width mm (in) 383 (15.05) 337 (13.25) mm (in) 1061 (41.75) Overall Height mm (in) 1188 (46.75) mm (in) 1315 (51.75) mm (in) 433 (17.05) Transom Height mm (in)
  • Page 38 Cooling System Forced Water Cooling Exhaust System Through-the-prop Exhaust Ignition System Flywheel Magneto CD Ignition MFS 6CZ: TDC0° - BTDC22° Ignition Timing MFS 8C: TDC0° - BTDC32° MFS 9.8C/9.9CY: TDC0° - BTDC30° Spark Plug Equivalent to NGK DCPR6E Alternator Output 12 V–7.0 A...
  • Page 39 Over-Revolution Engine speed is controlled at 6400min-1(rpm) or less for MFS 8C, 9.8C and Protection 9.9CY and 6200 min-1 (rpm) or less (High Speed ESG) for MFS 6CZ. Warning lamp is lit, and warning buzzer sound continuously. Engine Oil Pressure Engine speed is controlled at 2800 min (rpm) or less (Low Speed ESG).

  • Page 40: Maintenance Data

    Service Data 6. Maintenance Data Description Item Standard Value Compression pressure (reference value) Note) After warming up, remove all the spark Engine 0.88 MPa plugs and injector connectors, then take measurements with the throttle fully opened. IN: 0.10 – 0.15 mm (0.0040 – 0.0060 in) Valve Clearance EX: 0.20 –...

  • Page 41: Correction Method

    Functional Limit Correction Method Check if rotating parts, sliding parts and sealing parts cause compression leakage. Adjust to specified range IN: ø5.46 mm (0.2150 in) Replace if less than specified limit EX: ø5.44 mm (0.2142 in) IN: 0.05 mm (0.0002 in) Replace if more than specified limit EX: 0.03 mm (0.0012 in) IN: ø5.55 mm (0.2185 in)
  • Page 42 Service Data Description Item Standard Value Cylinder Liner Inner Diameter Use a cylinder gauge etc. to measure the ø54.990 – 55.005 mm (2.1650 – 2.1656 in) inner diameter Seizure, Cylinder Liner Damage or Wear Cylinder Block Distortion or Damage on Mating Surface Distortion: 0.05 mm (0.0020 in) or less Deposition in Water Jacket Small End Inner Diameter...
  • Page 43 Functional Limit Correction Method ø55.06 mm (2.1677 in) Replace if more than specified limit If the difference between the most worn out area and least worn out area of the liner inner diameter exceeds the specified value, Difference of 0.05 mm (0.0020 in) or less between the most worn the inner diameter should be bored to ø55.5 ±...
  • Page 44 Service Data Description Item Standard Value Plug Type DCPR6E (NGK) Spark Plug Spark Gap 0.8 – 0.9 mm (0.0315 – 00354 in) Primary Coil Resistance 0.30 Ω ± 15% (20°C) Ignition Coil Secondary Coil Resistance 8.5 kΩ ± 20% (20°C) Alternator (MAX) 12 V–84 W 1000 r/min, 14 V, 2 A or more...
  • Page 45 Functional Limit Action To Be Taken Clean and remove the carbon stains or damage Replace if the electrode is worn out significantly Spark gap 1.2 mm (0.0472 in) Replace if out of standard value Replace if out of standard value Replace if out of standard value Replace if out of standard value Replace with new part...

  • Page 46: Standard Value

    Service Data Description Item Standard Value Oil Seal Parts Wear, Damage Wear Exhaust cover: 1 piece Gear case (trim tab): 1 piece Anodes Gear case: 1 piece (MFS9.9CX only) Lower mount bracket: 1 piece (MFS9.9CX only) Clamp bracket: 2 pieces (PTT model only) 2-18 4st 6/8/9.9 2024...
  • Page 47 Functional Limit Action To Be Taken When the lips are deteriorated, degraded or damaged, or when the tightening margin is reduced to 0.5 mm (0.0197 in) due Replace with new part to wear Replace if severely worn out 4st 6/8/9.9 2024 2-19...

  • Page 48: Tightening Torque Data

    Service Data 7. Tightening Torque Data Tightening Torque Type of Fastened Components Wrench A Screw B x Pitch Fastener N·m lb·ft kgf·m First Tightening Torque M8x1.25 Bolt Second Tightening Torque Cylinder Head Installation Bolt (Cylinder Block and Cylinder Head) First Tightening Torque M6x1.0 Bolt Second Tightening Torque...
  • Page 49 Tightening Torque Type of Fastened Components Wrench A Screw B x Pitch Fastener N·m lb·ft kgf·m Tilt Cylinder Pin (Upper) M6x1.0 Bolt Mounting Bolt Tilt Cylinder (Lower) M8x1.25 Bolt Mounting Bolt Retaining Screw M8x1.25 Bolt PT Unit Pump Mounting Screw Bolt Motor Assy Mounting Bolt Bolt...

  • Page 50: Sealant Application Locations

    Service Data 8. Sealant Application Locations Loctite ThreeBond Loctite ThreeBond Location of Use 1342 1327 1373B 5910 7781 1521 1530D Cam Shaft Oil Seal (Cam Shaft) Rocker Arm Rocker Arm Shaft Rocker Arm Spring Washer (Rocker Arm) Valve (IN, EX) Cylinder Head Valve Spring Valve Spring Seat...
  • Page 51 Remarks Shinetsu Silicone KS-64 DEXRON–III ● Bearing, Cam Unit ● ● Outer Surface, Press Fit ● Bearing, Slipper Face ● Outer Face ● Entire Surface ● Entire Surface ● Shaft, Stem Head ● Entire Surface ● Entire Surface ● Entire Surface ●...
  • Page 52 Service Data Loctite ThreeBond Loctite ThreeBond Location of Use 1342 1327 1373B 5910 7781 1521 1530D O-ring (Fuel Injector Assy) ● Fuel Rail Bolt (Fuel Rail Installation) High-Pressure Fuel Hose Hose (to ISC valve) Intake Silencer Breather Hose (to Cylinder Head Cover) Rubber Mount VST Front Assembly Collar...
  • Page 53 Remarks Shinetsu Silicone KS-64 DEXRON–III ● Entire Surface Thread ● Can be applied to the end of the hose when inserting into the nipple ● Can be applied to the end of the hose when inserting into the silencer ● Can be applied to the end of the hose when inserting into the silencer ●...
  • Page 54 Service Data Loctite ThreeBond Loctite ThreeBond Location of Use 1342 1327 1373B 5910 7781 1521 1530D Drive Shaft (Spline) Drive Shaft Ball Bearing Needle Bearing Inner Oil Seal (Lower Pump Case) Pump Case Liner Water Pipe Seal (Lower) Gear Case O-Ring (Cam Rod Bushing Inner Side) O-Ring (Cam Rod Bushing Outer Side) Bolt (Pump Case)
  • Page 55 Remarks Shinetsu Silicone KS-64 DEXRON–III ● Crankshaft Side Spline ● At press fitting ● At press fitting ● ● Outer Surface, Press Fit ● Impeller Sliding Area ● Inner Face ● Entire Surface ● Entire Surface ● Thread ● At press fitting ●...
  • Page 56 Bushing (steering shaft arm side) Grease Fitting ● Top Cowl Top Cowl Seal ● Bolt (Fuel Connector) ● Bottom Cowl Bolt (fuel connector stay) Grommet (for Tohatsu tiller model) ● Nipples, Sealing Plugs ● Other Reuse Pre-coated Bolts PT Unit 2-28 4st 6/8/9.9 2024...
  • Page 57 Remarks Shinetsu Silicone KS-64 DEXRON–III ● Sliding Face (except slide adjustment section) ● Wire Section Thread Thread (tiller handle embedded side) Thread (nut mounting side) Press Fit ● Sliding Face ● Entire Surface ● Entire Surface ● Entire Surface ● Grease injection after completing the bracket assembly Rear Side Latch Thread...
  • Page 58 Service Data 2-30 4st 6/8/9.9 2024...

  • Page 59: Maintenance

    Maintenance 1. Special Tools ………………………………… 3-2 15) Adjustment of Throttle Cable (Tiller handle model) ……………………………… 3-22 2. Inspection Schedule ………………………… 3-3 16) Adjustment of Shift/Throttle Cable 3. Inspection Items …………………………… 3-4 (Remote Control Model) ……………………… 3-24 1) Inspection of Top Cowl ………………………… 3-4 17) Inspection of Shift Lever Gear Operations 3-28 2) Inspection of Fuel System Piping ……………...

  • Page 60: Special Tools

    Maintenance 1. Special Tools Spring Pin Tool A (ø3.0) Spring Pin Tool B (ø3.0) Spring Pin Tool A (ø3.5) Spring Pin Tool B (ø3.5) P/N. 345-72227-0 P/N. 345-72228-0 P/N. 369-72227-0 P/N. 369-72228-0 Removing spring pin Installing spring pin Removing spring pin Installing spring pin Tachometer Compression Gauge...

  • Page 61: Inspection Schedule

    2. Inspection Schedule Inspection interval Every 50 Every 100 Every 200 Every 400 Inspection item Inspection procedure Remarks First 20 hours hours or 3 hours or 6 hours or 1 hours or 2 or 1 month months months year years Check and Clean/ ○...

  • Page 62: Inspection Items

    Maintenance 3. Inspection Items 1) Inspection of Top Cowl Push the top cowl with both hands to check the rattling and tightening condition. 2) Inspection of Fuel System Piping Ch e c k th e fu e l sy ste m piping for fu e l le ak , dir t , deterioration and damage, and replace or repair parts if necessary.

  • Page 63: Inspection Of Fuel Tank

    3) Inspection of Fuel Tank Turn the fuel pickup elbow 2 of the fuel tank 1 to the left and remove it, and clean the filter 3. Remove dirt and water from the fuel tank if any. 2 Fuel Pickup Elbow 3 Filter 4) Inspection of Fuel Filter CAUTION...

  • Page 64: Replacement Of Engine Oil

    Lower Limit 600 ml (0.6 US qt.) 1 Oil Level Gauge a Upper Limit b Lower Limit 2. Oil Specification Recommended Engine Oil: Tohatsu 4-Stroke Engine Oil 10W – 40 Recommended Engine Oil Grade: 10W – 30 API: SH, SJ, SL SAE: 10W-30, 10W-40...
  • Page 65 6. Tilt down the outboard motor to make it vertical. 7. Pull the bottom of the cowl latch to release the lock, and lift the top cowl to remove it. 8. Remove the oil filler cap 2 and pour new engine oil into the oil inlet 3 until the oil level reaches a point somewhere between the upper and lower limit marks while checking the oil level gauge 4.

  • Page 66: Inspection Of Gear Oil Quantity

    3. Replenish the gear oil to the specified level if it is insufficient. Recommended Gear Oil: Tohatsu Gear Oil Recommended Gear Oil Grade: API: GL-5 SAE: #80-90 If the shortage is large, replenish through the lower oil plug hole.
  • Page 67 2. Remove the lower unit installation bolts, and pull the lower unit downward to remove it. 3. Remove the pump upper case 3. 4. Remove the impeller 4 and check it. 5. Check the pump case (upper) to see if there is any deformation.

  • Page 68: Replacement Of Gear Oil

    Recommended Gear Oil: Tohatsu Gear Oil Recommended Gear Oil Grade: API: GL-5 SAE: #80-90 Quantity of Gear Oil: 320 ml (11 US fl.oz)

  • Page 69: Inspection Of Gear Case (For Leakage)

    9) Inspection of Gear Case (for leakage) 1. Drain the gear oil. 2. Remove the upper oil plug 1 and connect a commercially available leakage tester to the hole. 3. Apply the specified pressure to the gear case, and check if the pressure is maintained for 10 seconds.

  • Page 70: Inspection Of Timing Belt

    Maintenance 10) Inspection of Timing Belt 1. Loosen the screw and disconnect the upper starter lock cable. 2. Remove the band and bolts (3 locations), and remove the recoil starter. 3. Disconnect the vent hose 1 and remove the belt cover 2.

  • Page 71: Replacement Of Timing Belt

    11) Replacement of Timing Belt 1. Remove the recoil starter and belt cover. 2. Using the flywheel puller kit 1, loosen the flywheel nut and remove it. Flywheel Puller Kit : P/N. 3V1-72211-1 3. Use the flywheel puller kit to remove the flywheel 2 and key.
  • Page 72 Maintenance CAUTION To prevent damages to engine and special tools, tighten flywheel puller set bolts evenly and keep flywheel puller parallel to flywheel while working. 4. Disconnect the alternator connector and remove the alternator 3. 5. Turn the drive pulley4 in the clockwise direction, and align the "...
  • Page 73 6. Install and secure the crankshaft holder 6 on the crankshaft. 7. Loosen drive pulley nut 7 and remove it. Remove belt guide 8. • Use a 32-mm socket wrench and 36-mm ring wrench for this step. • When loosening the nut of drive pulley 7, be careful not to turn the driven pulley 5.
  • Page 74 Maintenance 10. Make sure that the " ▲ " mark a of the drive pulley is aligned with the " ● " mark b of the cylinder block. The No.1 cylinder should be at the top dead center of the compression stroke. 11.
  • Page 75 14. Tighten timing pulley nut to specified torque. • Put pulley nut with chamfered face down. • Use a 32-mm socket wrench and 36-mm ring wrench for this step. Crankshaft Holder 6: P/N. 31H-72815-0 Drive Pulley Nut: 64 N·m (47 lb·ft) [6.4 kgf·m] 6 Crankshaft Holder 15.

  • Page 76: Inspection Of Spark Plugs

    Maintenance 18. Install the belt cover 0, and connect the vent hoses q. Install the vent hoses in their original location on the belt cover. 19. Install the recoil starter, then install the bolts (3 locations) and the band. • At parth, secure the ISC valve bracket and recoil starter with bolts.

  • Page 77: Inspection Of Compression Pressure

    2. Use a spark plug cleaner or wire brush to clean the spark plug electrodes 1. Replace if necessary. 3. Check the electrode for any corrosion or excessive buildup of carbon, and the washer 2 for any damage. Replace if necessary.

  • Page 78: Inspection And Adjustment Of Valve Clearance

    Maintenance 6. Fully open the throttle and crank the engine until the compression gauge indication stabilizes, then measure the compression pressure. Compression Pressure (reference value): 500 (rpm) 0.88 MPa (128 psi) [9.0 kgf/cm Compression pressure is affec ted by the cranking speed, and normally varies by about 10% to 20%.
  • Page 79 4. Turn the recoil starter slowly to align the " ● 1" mark a on driven pulley 3 with " ▲ " mark b on the cylinder head. The No.1 cylinder should be at the top dead center of the compression stroke. 5.

  • Page 80: Adjustment Of Throttle Cable (Tiller Handle Model)

    Maintenance 8. Turn the flywheel in the clockwise direction to align the "2" mark cof the driven pulley 3 with the " ▲ " mark b of the cylinder head. 9. Check No. 2 cylinder's intake and exhaust valve clearances. Adjust the gap if it is less than specified value.
  • Page 81 3. Insert throttle cable 2, which has a larger inner protrusion, into recess 3 on the top of the throttle drum, and secure temporarily with nut 4. Position it at the center of the threaded section. 4. Set the throttle grip to the fully closed position. 5.

  • Page 82: Adjustment Of Shift/Throttle Cable (Remote Control Model)

    Maintenance 8. Fully open the throttle grip until throttle lever 9 on the throttle body touches fully open stopper c, then tighten screw 0 while pushing the end of throttle rod 8 in the direction of the arrow. 9. Set the throttle grip to the fully closed position and check that the throttle lever on the throttle body touches fully closed stopper d.
  • Page 83 4. Set the control lever on the remote control box to the fully open position. 5. Place throttle drum 4 against the fully open stopper a, and align nut 6 at the end of the remote control cable with the position of cable joint 5. 6.
  • Page 84 Maintenance 9. Set control lever q to neutral (N) and free accelerator lever w to fully closed position d. 10. Set shift arm e to the forward (F), neutral (N), and reverse (R) positions, and then set it to the neutral (N) position. 11.
  • Page 85 14. Check that the outboard motor shifts in when the control lever is lowered to the Forward (F) side f or reverse (R) side g until it stops (approximately 32˚), and that the throttle is activated and fully opened when the control lever is lowered further.

  • Page 86: Inspection Of Shift Lever Gear Operations

    Maintenance 19. Install the remote control cable stay cover. CAUTION Be careful not to nip the PT switch cord with the cover and bottom cowl. (EPT Model) 17) Inspection of Shift Lever Gear Operations Check that the gear shift operates smoothly when shifting from neutral (N) to forward (F) or reverse (R).

  • Page 87: Inspection Of Idle Speed

    3. Fit cable joint 5 onto shift arm 1, and align nut 6 of the remote control cable with the cable joint. When adjusting the position of the cable joint, push in the remote control cable to remove any play. 4.

  • Page 88: Inspection Of Ignition Timing

    Maintenance 19) Inspection of Ignition Timing Adjustment method: Automatic control. No adjustment required. Run the engine and use a timing light to check the ignition timing. 11 timing marks are found on the side of the flywheel (TDC0°, ATDC5°, 10°, BTDC5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°), so the ignition timing is read from the mark in the center of the starter case window.

  • Page 89: Inspection Of Anodes

    20) Inspection of Anodes Inspection of Conductivity CAUTION If the anode is not getting smaller, there is a possibility Do not coat the anode or trim tab with oil, grease or paint, or their anti-galvanic corrosion function will that conductivity is not being maintained correctly. not work normally.

  • Page 90: Replacement Of Anodes

    Maintenance 21) Replacement of Anodes Anodes protect the outboard motor from galvanic corrosion (corrosion of metal due to very weak electric current). Anodes are used in the gear case and power unit. Replace an anode if the size is reduced to 2/3 that of a new one.

  • Page 91: Inspection Of Propeller

    23) Inspection of Propeller 1. Check the propeller blades and splines for cracks, damage, wear, and corrosion. Replace if necessary. 24) Inspection of Thermostat 1. Loosen the nut on the thermostat cover and remove thermostat 1. 2. Hang thermostat 2 in a vessel containing water. 3.

  • Page 92: Inspection Of Cooling Water Passage

    Maintenance 4. Measure valve lif t of thermostat when prescribed temperature has been reached. Replace if less than the specified value. Water Temperature Valve Lift a 75±1.5°C 3.0 mm (0.12 in) or more (167±3°F) 5. Install thermostat, new gasket and cover. Install the thermostat with the air bleeding valve recess b facing upward.

  • Page 93: Flushing With Water

    26) Flushing with Water WARNING Exhaust gas contains carbon monoxide, which may result in gas poisoning. Do not start the engine with the outboard motor placed in an enclosed area such as a boat house etc. CAUTION Touching a rotating propeller may lead to injury. Be sure to remove the propeller before running the engine on land.

  • Page 94: Inspection Of Battery

    Maintenance 27) Inspection of Battery 1. Inspect the electrolyte level. If it is lower than the "LOW" mark a, add distilled water until the level is between the "UP" and "LOW" marks. 2. Measure the specific gravity of the electrolyte. Fully charge the battery if the specific gravity is less than the specified value.

  • Page 95: Grease Points

    28) Grease points Apply water proof grease to the parts shown below or pour it via grease nipples. 4st 6/8/9.9 2024 3-37...
  • Page 96 Maintenance 3-38 4st 6/8/9.9 2024...

  • Page 97: Fuel System (Fuel Injection)

    Fuel System (Fuel Injection) 1. Special Tools ………………………………… 4-2 5. Ignition System ……………………………… 4-23 2. Piping Arrangement Diagram ……………… 4-3 (1) Configuration of Ignition System ………… 4-23 Fuel Hose, Vent Hose, Breather Hose, Cooling (2) Ignition Control ………………………………… 4-24 Water Hose ……………………………………………… 4-3 1) Ignition Timing Control …………………………...

  • Page 98: Special Tools

    Fuel System (Fuel Injection) Fuel System (Fuel Injection) 1. Special Tools Vacuum/Pressure Gauge Pressure Gauge Assembly Tachometer P/N. 3AC-99020-1 P/N. 3T5-72880-0 P/N. 3AC-99010-0 Measurement of fuel Measuring engine revolution Inspecting pressure pressure speed 4st 6/8/9.9 2024...

  • Page 99: Piping Arrangement Diagram

    2. Piping Arrangement Diagram Fuel Hose, Vent Hose, Breather Hose, Cooling Water Hose Port Side Starboard Side Ref. No. Part Name ① Fuel Hose (Fuel Connector → Fuel Filter) ② Fuel Hose (Fuel Filter → Fuel Pump) ③ Fuel Hose (Fuel Pump → Vapor Separator) High Pressure Fuel Hose (Vapor Separator →...

  • Page 100: Parts Layout

    Fuel System (Fuel Injection) Fuel System (Fuel Injection) 3. Parts Layout Intake Manifold & Fuel Pump 4st OIL 4 N·m (3 lb·ft) [0.4 kgf·m] 5 N·m (3.7 lb·ft) [0.5 kgf·m] 1342 1 1 342 1342 4st 6/8/9.9 2024...
  • Page 101 Ref. Part Name Q'ty Remarks Fuel Rail Assy * Fuel Rail * Fuel Injector Assy * Seal Ring Do not reuse. * Valve Assy (Pressure Check) * Valve Cap * Nipple Bolt Insulator Band Do not reuse. Vapor Separator Assy * Cover * Seal Do not reuse.
  • Page 102 Fuel System (Fuel Injection) Fuel System (Fuel Injection) 4st OIL 4 N·m (3 lb·ft) [0.4 kgf·m] 5 N·m (3.7 lb·ft) [0.5 kgf·m] 1342 1 1 342 1342 4st 6/8/9.9 2024...
  • Page 103 Ref. Part Name Q'ty Remarks Fuel Pump Assy O-ring Do not reuse. Screw Hose Clip ø9.4 Clip ø9.4 Hose Fuel Filter Assy * Cup * Filter * O-ring Do not reuse. * O-ring Do not reuse. * Drain Valve * Seal Do not reuse.
  • Page 104 Fuel System (Fuel Injection) 4st OIL 4 N·m (3 lb·ft) [0.4 kgf·m] 5 N·m (3.7 lb·ft) [0.5 kgf·m] 1342 1 1 342 1342 4st 6/8/9.9 2024...
  • Page 105 Ref. Part Name Q'ty Remarks Collar Washer 6-16-1.5 Bolt Throttle Rod Breather Hose Fuel Hose W/Protector Restrictor Water Nipple Hose Clip ø9.4 Clamp 6.5-14L Bolt Throttle Drum Assy Throttle Wire Bracket Bolt Band Do not reuse. MF EF EFT 4st 6/8/9.9 2024...

  • Page 106: Magneto & Electric Parts

    Fuel System (Fuel Injection) Fuel System (Fuel Injection) Magneto & Electric Parts 58 N·m (43 lb·ft) [5.8 kgf·m] 4 N·m (3 lb·ft) [0.4 kgf·m] 8 N·m (6 lb·ft) [0.8 kgf·m] 25 26 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 2.7 N·m (2.0 lb·ft) [0.27 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m]...
  • Page 107 Ref. Part Name Q'ty Remarks Flywheel Assy Alternator Assy Pulser Coil Key 13.4-5-4 Nut 12-P1.25 Washer Bolt Bolt Electrical Bracket Collar Bolt ECU Assy (9.8) ECU Holder Cord Assy Grommet Oil Pressure Switch Cable Terminal Plug Diagnostic Connector Cap Cable Terminal Plug Rubber Mount Protector Band...
  • Page 108 Fuel System (Fuel Injection) 58 N·m (43 lb·ft) [5.8 kgf·m] 4 N·m (3 lb·ft) [0.4 kgf·m] 8 N·m (6 lb·ft) [0.8 kgf·m] 25 26 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 2.7 N·m (2.0 lb·ft) [0.27 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m]...
  • Page 109 Ref. Part Name Q'ty Remarks Bolt EF EFT EP EPT Terminal Cap EF EFT EP EPT Terminal Cap EF EFT EP EPT Terminal Cap EF EFT EP EPT Starter Cable L=200 EF EFT EP EPT Neutral Switch Bracket EF EFT EP EPT Neutral Switch EF EFT EP EPT Neutral Switch Actuator...

  • Page 110: Fuel Tank

    Fuel System (Fuel Injection) Fuel System (Fuel Injection) Fuel Tank Fig.13-3 12-2 12-1 Ref. Ref. Part Name Remarks Part Name Remarks Q'ty Q'ty Primer Bulb Assy 12-1 Fuel Tank Assy 12L for USA Model Joint Assy (Inlet) 12-2 Fuel Tank Assy 12L 13 Fuel Tank Cap Assy for USA Model Clamp...

  • Page 111: Ecu System

    4. ECU System (1) Configuration of ECU System ① Fuel Tank The ECU uses various sensors to precisely control the injected fuel amount and ignition timing. ② Fuel Regulator ③ Vapor Separator ④ Fuel Feed Pump (FFP) ⑤ ECU ⑥ Ignition Coil ⑦...

  • Page 112: Sensors

    Fuel System (Fuel Injection) 1) Sensors Individual sensors detect the engine operating conditions and sends signals regarding the information to the ECU. 1. Pulser Coil [Crank Position Sensor] Pulser coils function as crank position sensors. As the flywheel rotates, the pulser coil sends a crank position signal to the ECU.
  • Page 113 5. Oil Pressure Switch The oil pressure switch is located on the port side of the engine block, protruding into the oil passage. The oil pressure switch sends an oil pressure low signal to the ECU. The ECU activates the low speed ESG and warning lamp based on this information.

  • Page 114: Actuators

    Fuel System (Fuel Injection) 2) Actuators The actuator receives signals from the ECU to control the air/fuel ratio, ignition advance angle and idle revolution speed. 1. ISC (Idle Speed Control) Valve ISC is also referred to as IAC (Idle Air Control). The ISC valve is a solenoid valve with a built-in spring that is operated electrically to control the air intake quantity that bypasses the closed throttle valve.

  • Page 115: Control System (Ecu)

    4. Controls the engine low speed ESG function. 5. Controls the engine high speed ESG function. Memorizes engine operation information. Monitoring and failure diagnosis can be carried out using a PC on which TOHATSU DIAGNOSTICS (software) is installed and diagnostics harness. (2) Control System The ECU (Electronic Control Unit) is installed in the crankcase via a bracket.

  • Page 116: Fuel Injection Control

    Fuel System (Fuel Injection) (3) Fuel Injection Control The ECU calculates the intake air quantity based on the engine revolution speed and intake manifold pressure (intake vacuum pressure) to determine the fuel injection amount. During engine startup, warm-up, acceleration/deceleration, and idling, the ECU performs correction control based on information from the sensors.

  • Page 117: Control Of Fuel Feed Pump (Ffp)

    (4) Control of Fuel Feed Pump (FFP) During normal operation: ECU performs on/off control for fuel feed pump (FFP) by using output signal from its pump control circuit. At starting: Pump control circuit outputs a signal to the pump (FFP), and power is supplied to the DC motor to drive the pump (FFP).

  • Page 118: Warning Buzzer And Lamp (Led), And Control Of Engine Revolution Speed

    Fuel System (Fuel Injection) (6) Warning Buzzer and Lamp (LED), and Control of Engine Revolution Speed Warning System When an abnormality occurs on the engine, warning buzzer sounds and warning lamp (LED) is lit or blinks. In such case, engine speed is controlled but engine is not stopped. 1) Location of Warning Buzzer and Lamp (LED) •...

  • Page 119: Ignition System

    5. Ignition System For ignition system, CD ignition system is adopted, and ECU's electronic ignition timing control system controls the timing to the most suitable state according to current operating conditions. As engine is started, electric current is generated in the exciter coil of alternator. Which is input to ECU's regulator to feed power needed for operations of ignition coil, fuel injector and fuel feed pump (FFP).

  • Page 120: Ignition Control

    Fuel System (Fuel Injection) (2) Ignition Control The ECU's microcomputer is pre-programmed with optimal ignition timings according to the condition of the engine. The ECU obtains information about the engine operating status such as the revolution speed, throttle opening, manifold pressure (air intake vacuum pressure), cooling water temperature etc. based on the signals from the above- mentioned sensors to ignite the fuel at the optimal ignition timing.

  • Page 121: Fuel Feed System

    (3) Fuel Feed System The fuel pump 3 [low-pressure mechanical] draws fuel from the fuel tank and supplies it to the fuel feed pump 5 (FFP) [high-pressure electric] inside the vapor separator 4 through the fuel connector 1 and fuel filter 2. Highly pressurized fuel is fed into the fuel rail 7 and fuel injector, and is then injected into the intake manifold.

  • Page 122: Components Of Fuel Feed System

    Fuel System (Fuel Injection) 6. Components of Fuel Feed System 1) Fuel Pump [Low Pressure Mechanical Pump] The fuel pump is a diaphragm pump that is operated mechanically by the camshaft. Due to the cooling system, cooling water enters from the vapor separator, cools the fuel, and then discharges to the cooling water check port.

  • Page 123: Fuel Regulator

    3) Fuel Regulator The fuel regulator located inside the vapor separator serves to keep the fuel pressure constant. The fuel regulator is located in the passage connecting the high-pressure side and the chamber (low-pressure side), with a spring inside that pushes a ball to seal it (valve closed). When the pressure in the high-pressure passage exceeds a certain level, the spring is compressed, the valve opens, and fuel is returned to the chamber, maintaining constant fuel pressure on the high-pressure side.

  • Page 124: Outline Of Fuel Injection System

    Fuel System (Fuel Injection) 7. Outline of Fuel Injection System 1) Air Intake System The air intake system consists of intake manifold 1, throttle position sensor 2, throttle body 3, ISC (idle speed control) valve 4, and T-MAP (manifold pressure and temperature) sensor 5. The fuel rail and fuel injector are installed in the intake manifold 1.

  • Page 125: Inspection Items

    8. Inspection Items 1) Inspection of Fuel Supply System Check the fuel system piping for fuel leak, dirt, deterioration and damage, and replace or repair parts if necessary. 2) Inspection of Filter 1. Check if there is any dirt in fuel filter 1, or if there is any fuel varnish, debris, deposits and contamination by foreign matter or water in the fuel filter cup 2, or if there are any cracks.
  • Page 126 Fuel System (Fuel Injection) 4. Remove and inspect the fuel filter (suction side) ⑦ from the fuel feed pump (FFP) in the vapor separator. Replace it if it is dirty. 4-30 4st 6/8/9.9 2024...

  • Page 127: Inspection Of Fuel Pump

    3) Inspection of Fuel Pump 1. Remove the fuel hoses (2 pcs.) from the fuel pump. 2. Connect the vacuum/pressure gauge to the inlet of the fuel pump. 3. Close the fuel pump outlet with your finger and apply the specified pressure.

  • Page 128: Measurement Of Fuel Pressure

    Fuel System (Fuel Injection) 5) Measurement of Fuel Pressure 1. Remove the cap ⑦. 2. Connect the pressure gauge ⑦ as shown in the figure. WARNING • Before measurement, check that pressure relief valve is fully closed. • B e fo r e c o nn e c t in g p r e s s ur e g a u g e , c o v e r connection between pressure gauge and valve with clean and dry cloth to prevent fuel from releasing.

  • Page 129: Draining Fuel

    6) Draining Fuel 1. Remove the cap 1. 2. Connect the pressure gauge assembly 2 as shown in the figure, place a vessel below the pressure relief hose, and open the pressure relief valve 3 to release the fuel pressure. WARNING Be sure to reduce the fuel pressure in the high pressure fuel passage before ser vicing the fuel...

  • Page 130: Inspection Of Vapor Separator

    Fuel System (Fuel Injection) 2. Remove the needle valve 1, float pin 2, and float. 8) Inspection of Vapor Separator 1. Check the needle valve for bend and wear. Replace if necessary. 2. Check the float for deformation. Replace if necessary. 3.

  • Page 131: Reassembly Of Vapor Separator

    9) Reassembly of Vapor Separator 1. Attach the float chamber to the vapor separator. 2. Reassemble all parts that were removed. Check that the hose is reconnected correctly. 10) Inspection of ISC (Idle Speed Control) 1. Use the diagnosis system to check operation of the ISC (Idle Speed Control) valve.
  • Page 132 Fuel System (Fuel Injection) 4-36 4st 6/8/9.9 2024...
  • Page 133 Power Unit 1. Special Tools ………………………………… 5-2 22) Installation of Rocker Arm Shaft …………… 5-52 2. Parts Layout …………………………………… 5-3 23) Installation of Oil Pump ………………………… 5-53 Engine ……………………………………………………… 5-3 24) Installation of Cylinder Head ………………… 5-54 Magneto & Electric Parts ………………………… 5-4 25) Disassembly of Cylinder Block ………………...

  • Page 134: Power Unit

    Power Unit 1. Special Tools Flywheel Puller Kit Piston Slider Compression Gauge Torque Wrench P/N. 3V1-72211-1 P/N. 3V1-72871-0 P/N. 3AC-99030-0 P/N. 3AC-99070-0 Measuring compression Removing and installing flywheel Installing piston Adjusting valve clearance pressure ø34.5 x ø17.5 Crank Shaft Holder Valve Clearance Driver Driver Rod Oil Seal Attachment...

  • Page 135: Parts Layout

    2. Parts Layout Engine 1 15 N·m (11 lb·ft) [1.5 kgf·m] 2 30 N·m (22 lb·ft) [3.0 kgf·m] 1 15 N·m (11 lb·ft) [1.5 kgf·m] 2 30 N·m (22 lb·ft) [3.0 kgf·m] Ref. Part Name Remarks Q'ty Recoil Starter Oil Level Gauge Power Unit Stay Cover Grommet...

  • Page 136: Magneto & Electric Parts

    Power Unit Magneto & Electric Parts 58 N·m (43 lb·ft) [5.8 kgf·m] 4 N·m (3 lb·ft) [0.4 kgf·m] 8 N·m (6 lb·ft) [0.8 kgf·m] 25 26 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 2.7 N·m (2.0 lb·ft) [0.27 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m]...
  • Page 137 Ref. Part Name Q'ty Remarks Flywheel Assy Alternator Assy Pulser Coil Key 13.4-5-4 Nut 12-P1.25 Washer Bolt Bolt Electrical Bracket Collar Bolt ECU Assy (9.8) ECU Holder Cord Assy Grommet Oil Pressure Switch Cable Terminal Plug Diagnostic Connector Cap Cable Terminal Plug Rubber Mount Protector Band...
  • Page 138 Power Unit 58 N·m (43 lb·ft) [5.8 kgf·m] 4 N·m (3 lb·ft) [0.4 kgf·m] 8 N·m (6 lb·ft) [0.8 kgf·m] 25 26 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 2.7 N·m (2.0 lb·ft) [0.27 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m]...
  • Page 139 Ref. Part Name Q'ty Remarks Bolt EF EFT EP EPT Terminal Cap EF EFT EP EPT Terminal Cap EF EFT EP EPT Terminal Cap EF EFT EP EPT Starter Cable L=200 EF EFT EP EPT Neutral Switch Bracket EF EFT EP EPT Neutral Switch EF EFT EP EPT Neutral Switch Actuator...

  • Page 140: Intake Manifold & Fuel Pump

    Power Unit Intake Manifold & Fuel Pump 4 N·m (3 lb·ft) [0.4 kgf·m] 5 N·m (3.7 lb·ft) [0.5 kgf·m] 4st OIL 1342 1 1 342 1342 4st 6/8/9.9 2024...
  • Page 141 Ref. Part Name Q'ty Remarks Fuel Rail Assy * Fuel Rail * Fuel Injector Assy * Seal Ring Do not reuse. * Valve Assy (Pressure Check) * Valve Cap * Nipple Bolt Insulator Band Do not reuse. Vapor Separator Assy * Cover * Seal Do not reuse.
  • Page 142 Power Unit 4 N·m (3 lb·ft) [0.4 kgf·m] 5 N·m (3.7 lb·ft) [0.5 kgf·m] 4st OIL 1342 1 1 342 1342 5-10 4st 6/8/9.9 2024...
  • Page 143 Ref. Part Name Q'ty Remarks Fuel Pump Assy O-ring Do not reuse. Screw Hose Clip ø9.4 Clip ø9.4 Hose Fuel Filter Assy * Cup * Filter * O-ring Do not reuse. * O-ring Do not reuse. * Drain Valve * Seal Do not reuse.
  • Page 144 Power Unit 4 N·m (3 lb·ft) [0.4 kgf·m] 5 N·m (3.7 lb·ft) [0.5 kgf·m] 4st OIL 1342 1 1 342 1342 5-12 4st 6/8/9.9 2024...
  • Page 145 Ref. Part Name Q'ty Remarks Collar Washer 6-16-1.5 Bolt Throttle Rod Breather Hose Fuel Hose W/Protector Restrictor Water Nipple Hose Clip ø9.4 Clamp 6.5-14L Bolt Throttle Drum Assy Throttle Wire Bracket Bolt Band Do not reuse. MF EF EFT 4st 6/8/9.9 2024 5-13...

  • Page 146: Pulley & Timing Belt

    Power Unit Pulley & Timing Belt 11 N·m (8 lb·ft) [1.1 kgf·m] 64 N·m (47 lb·ft) [6.4 kgf·m] 5-14 4st 6/8/9.9 2024...
  • Page 147 Ref. Part Name Q'ty Remarks Drive Pulley Key 10-3.7-3 Key 10-3.7-3 Belt Guide Nut Pulley Driven Pulley Washer Pre-Coated Bolt Timing Belt 4st 6/8/9.9 2024 5-15...

  • Page 148: Cylinder Head & Oil Pump

    Power Unit Cylinder Head & Oil Pump 1 6 N·m (4 lb·ft) [0.6 kgf·m] 2 10 N·m (7 lb·ft) [1.0 kgf·m] Fig.5 Fig.5 Fig.5 1 10 N·m (7 lb·ft) [1.0 kgf·m] 2 30 N·m (22 lb·ft) [3.0 kgf·m] 18 N·m (13 lb·ft) [1.8 kgf·m] 4st OIL 7 N·m (5 lb·ft) [0.7 kgf·m] 1342...
  • Page 149 Ref. Part Name Q'ty Remarks Cylinder Head Complete * Cylinder Head Assy * Intake Valve * Exhaust Valve * Valve Spring L=38.3 * Retainer * Cotter * Valve Spring Seat * Intake Valve Stem Seal Do not reuse. * Exhaust Valve Stem Seal Do not reuse.

  • Page 150: Cylinder & Crankcase

    Power Unit Cylinder & Crankcase 1 10 N·m (7 lb·ft) [1.0 kgf·m] 2 23.5 N·m (17 lb·ft) [2.35 kgf·m] 30 N·m (22 lb·ft) [3.0 kgf·m] 18 N·m (13 lb·ft) [1.8 kgf·m] 4st OIL 1342 1 1 342 1342 5910 5910 5910 5910 5-18...
  • Page 151 Ref. Part Name Q'ty Remarks Cylinder Block & Crankcase Assy * Nipple * Dowel Pin 6-12 * Bolt Thermostat Thermostat Cap Thermostat Cap Gasket Do not reuse. Bolt Exhaust Cover (Outer) Exhaust Cover Gasket Do not reuse. Bolt Anode Plug Assy * Anode Plug * O-ring 1.9-13 Do not reuse.

  • Page 152: Piston & Crankshaft

    Power Unit Piston & Crankshaft 4st OIL 1 6 N·m (4 lb·ft) [0.6 kgf·m] 2 12 N·m (9 lb·ft) [1.2 kgf·m] 5-20 4st 6/8/9.9 2024...
  • Page 153 Ref. Part Name Q'ty Remarks Connecting Rod Assy * Connecting Rod Assy Crankshaft Assy Plain Shaft Bearing (Brown) Oil Seal 36-50-7 Do not reuse. Oil Seal 30-45-8 Do not reuse. Piston Piston Ring Piston Ring Piston Ring (Oil) Piston Pin Piston Pin Clip Do not reuse.

  • Page 154: Top Cowl

    Power Unit Top Cowl 5-22 4st 6/8/9.9 2024...
  • Page 155 Ref. Part Name Q'ty Remarks Top Cowl Assy * Top Cowl Sub-assy ** Top Cowl Seal * Side Decal * Rear Decal (6) * Simpliq Decal * Fuel Injection Decal * Logo Decal 4st 6/8/9.9 2024 5-23...

  • Page 156: Recoil Starter

    Power Unit Recoil Starter 1342 1 1 342 1342 1741 1 1 741 1741 6 N·m (4 lb·ft) [0.6 kgf·m] 5-24 4st 6/8/9.9 2024...
  • Page 157 Ref. Part Name Q'ty Remarks Recoil Starter Assy * Wave Washer * Starter Spring * Starter Spring Case * Reel 　140 * Return Spring * Ratchet * Friction Spring * Bolt Starter Shaft * Friction Plate * Starter Rope 　4.5-1600 * Starter Handle * Rope Anchor * Starter Seal...

  • Page 158: Inspection Items

    Power Unit 3. Inspection Items 1) Inspection of Compression Pressure 1. Refer to "Inspection of Compression Pressure" in chapter 3. Compression Pressure (Reference value): At 500 min (rpm) 0.88 MPa (128 psi) [8.9 kgf/cm 2) Inspection of Oil Pressure 1. Place a rag below the oil pressure switch. 2.
  • Page 159 2. Remove the fuel hose (IN) 3. 3. Loosen screw 4 and remove link 5. 4. Remove throttle drum 6 and bracket 7. 5. Loosen screw 8 and remove starter lock cable 9. 4st 6/8/9.9 2024 5-27...
  • Page 160 Power Unit 6. Remove cooling water hose 0. 7. Disconnect the connectors for the indicator lamp, stop switch, neutral switch, start switch, fuse, and PT switch. • Disconnect the start switch and fuse connectors for the electric start model only. •...

  • Page 161: Removing Oil Strainer

    5) Removing Oil Strainer 1. Remove the power unit. (Refer to the section on removing the power unit) Place removed power unit assembly 1 on a stand with the port side (left side) facing down. 2. Remove oil strainer 2 and plunger 3 from power unit ass'y Before removing the oil strainer hose, note the arrangement of the hose.
  • Page 162 Power Unit 3. Disconnect the vent hose 1 and remove the belt cover 2. 4. Using the flywheel puller kit 3, loosen the flywheel nut and remove it. Flywheel Puller Kit : 　P/N. 3V1-72211-1 5. Use the flywheel puller kit to remove the flywheel 4 and key.
  • Page 163 7. Turn the drive pulley 6 in the clockwise direction, and align the " ▲ " mark a of the drive pulley with the " ● " mark b of the cylinder block. Check that the " ● 1" mark c of the driven pulley 7 and the "...

  • Page 164: Inspection Of Timing Belt

    Power Unit 10. While securing the crankshaft holder 8, remove the bolt q from the driven pulley 7. When loosening the driven pulley bolt, be careful not to turn the driven pulley. 11. Remove the timing belt 0. CAUTION Do not turn the drive pulley (crank shaft) or driven pulley with the timing belt removed.

  • Page 165: Installation Of Pulley And Timing Belt

    9) Installation of Pulley and Timing Belt CAUTION Do not turn the drive pulley or the driven pulley with the timing belt removed. Doing so can make pistons and valves inter fere with each other, possibly resulting in damages to these parts. 1.
  • Page 166 Power Unit 4. Install the timing belt 6. CAUTION • Be careful not to damage the timing belt during installation. • Do not twist, turn inside out, or sharply bend the timing belt. Doing so may cause damage. • Be careful not to allow oil or grease to adhere to the timing belt.
  • Page 167 8. Turn the crankshaft two full rotations in the clockwise direction, and check that the alignment marks of the pulleys are aligned. • Check that the crankshaft turns smoothly. • Make sure the " ▲ " mark a of the drive pulley is aligned with the "...

  • Page 168: Removal Of Cylinder Head

    Power Unit 10) Removal of Cylinder Head • No.1 piston is to be at top dead center of compression stroke (make sure both valves are close d).(Refer to the se c tion on the replacement of the timing belt.) • Removal or installation of parts can be made easier when some of them are assembled together.
  • Page 169 6. Remove the intake silencer 8. Remove the ground wires (main harness 9, starter solenoid 0, PT solenoid q) and the main harness connector w. • Power tilt model only: PT solenoid ground wire q • Remote control model only: Main harness connector w 8.
  • Page 170 Power Unit Remove the ground wire i (rectifier, ignition coil). 13. Remove the ignition coil o. 14. Remove the spark plugs p. 15. Remove the rectifier a. 16. Remove the throttle body s. 5-38 4st 6/8/9.9 2024...
  • Page 171 17. Remove the fuel filter d. 18. Remove fuel pump f. Remove the fuel rail g. 20. Remove the vapor separator h. 21. Remove the crank position sensor j. 4st 6/8/9.9 2024 5-39...
  • Page 172 Power Unit 22. Remove the oil pressure switch k and the fuel filter bracket l. 23. Remove the engine temperature sensor ;. 24. Remove the oil level gauge guide z. 25. Remove the cylinder head cover. 26. Remove the cylinder head bolts in the order shown in the diagram, then remove the cylinder head.
  • Page 173 27. Loosen the adjusting nut 4 of the rocker arm and fully loosen the adjusting screw 3. 28. Remove the oil pump 1. 28. Remove the rocker arm 2, adjusting screw 3, adjusting nut 4, spring 5, washer 6, and rocker arm shaft 7. •...

  • Page 174: Inspection Of Valve Spring

    Power Unit 32. Compress the valve spring 9 by using the compressor 0, remove the cotter q, and then remove the valve spring and valve v. • Valves, springs and other power unit related parts should be arranged in the order they are removed.

  • Page 175: Inspection Of Valve Guide

    13) Inspection of Valve Guide Before inspecting the valve guide, check that the valve stem outer diameter is within the specified limit. 1. Measure the valve guide inner diameter a. Replace the cylinder head if greater than the specified value. Valve Guide Inner Diameter a: Standard Value Intake/Exhaust Side: 5.51 mm (0.2169 in) Functional Limit:...

  • Page 176: Inspection Of Valve Seat

    Power Unit 14) Inspection of Valve Seat 1. Remove the carbon built up on the valve. 2. Evenly apply a thin coat of red lead to the valve seat. 3. Use a valve lapper (commercially available) to push the valve onto the valve seat lightly as shown in the diagram.

  • Page 177: Correction Of Valve Seat

    15) Correction of Valve Seat 1. Use valve seat cutter (commercially available item) to correct valve seat. 30˚ 45˚ 60˚ 2. Use a 45˚ seat cutter to grind the valve seat surface until it becomes smooth while rotating the cutter in the clockwise direction.
  • Page 178 Power Unit 5. Use a 45˚ seat cutter to adjust the contact width c of the valve seat to the specified value. 45˚ b Width before correction c Specified width 6. If the valve seat contact area is located in the center and the area is too wide, adjust the contact width to the 30˚...

  • Page 179: Inspection Of Rocker Arm And Rocker Arm Shaft

    9. Apply a thin coat of an abrasive compound to the entire valve seat contact area, and rub and polish the valve seat while knocking and turning the valve with a valve lapper (commercially available). CAUTION Perform the work by taking care not to allow the abrasive compound to adhere to the valve stem and valve guide.

  • Page 180: Inspection Of Camshaft

    Power Unit 17) Inspection of Camshaft 1. Measure the cam height. Replace if less than the specified value. Cam Height a: Standard Value Intake Side: 23.43 mm (0.9224 in) Exhaust Side: 23.46 mm (0.9236 in) Functional Limit: Cam Height a Intake Side: 23.3 mm (0.9173 in) Exhaust Side: 23.3 mm (0.9173 in) 2.

  • Page 181: Inspection Of Cylinder Head

    4. Measure the cylinder head journal inner diameter d and oil pump journal inner diameter e. Calculate the oil clearances. The values are d − b and e − c. Replace the camshaft, cylinder head, or oil pump if greater than the specified value.

  • Page 182: Inspection Of Oil Pump

    Power Unit 19) Inspection of Oil Pump 1. Use a micrometer, cylinder gauge, depth gauge, and thickness gauge to measure the dimensions shown below. Replace the oil pump if other than the specified value. Functional Limit Clearance between outer rotor and body a: 0.36 mm (0.0142 in) Clearance between outer and inner rotors b: 0.16 mm (0.0063 in)

  • Page 183: Installation Of Valves

    20) Installation of Valves 1. Apply oil to valve guide and attach new valve stem seal. 4st OIL Intake Side: Gray Exhaust Side: Green 4st OIL 2. Install the valve 2, valve spring seat 3, valve spring 4, and retainer 5 in the order shown in the diagram, then install the valve spring compressor 6.

  • Page 184: Installation Of Camshaft

    Power Unit 21) Installation of Camshaft 1. Apply 4-stroke engine oil on the outer circumference of the 4st OIL new oil seal 1 and install the camshaft. Oil Seal Attachment: Commercially available item Apply seal grease to lip of oil seal before installing LOR #101 �...

  • Page 185: Installation Of Oil Pump

    2. Install the rocker arms 2, washers 3, and springs 4 while inserting the rocker arm shaft 1 from the lower side of cylinder head 　. · Apply sufficient amount of engine oil to rocker arm and adjust screw after installing rocker arm. •...

  • Page 186: Installation Of Cylinder Head

    Power Unit 24) Installation of Cylinder Head The No.1 cylinder should be at the top dead center of the compression stroke. 1. After temporarily assembling the driven pulley, align the "1" mark a of the pulley ① to the " ▲ " mark b of the cylinder head.
  • Page 187 4. Install cylinder head with new gasket, and tighten bolts in the order shown in two steps to specified torque. CAUTION • Do not reuse the cylinder head gasket. Be sure to replace it with a new one. • Do not turn the timing pulley or camshaft pulley with the timing belt removed.

  • Page 188: Disassembly Of Cylinder Block

    Power Unit 25) Disassembly of Cylinder Block 1. Remove the thermostat cover 1, the exhaust cover 2, and the bolts. 2. Loosen the crankcase bolts in several steps in the order shown in the diagram and remove the crankcase. 1 - 8 3.

  • Page 189: Inspection Of Piston Outer Diameter

    26) Inspection of Piston Outer Diameter 1. Measure the piston outer diameter between the specified points. Replace if less than the specified value. Piston Outer Diameter a: Standard Value 54.96 mm (2.1638 in) Measurement Point b: 7 mm (0.28 in) above piston skirt bottom Functional Limit: 　54.90 mm (2.1614 in) 27) Inspection of Cylinder Inner Diameter...

  • Page 190: Inspection Of Piston Clearance

    Power Unit 28) Inspection of Piston Clearance 1. If the piston clearance is greater than the specified limit, replace the cylinder block, or replace the piston and piston rings as a set, or replace all of them. Piston Clearance (Cylinder inner diameter – Piston outer diameter): 0.020 –...

  • Page 191: Inspection Of Piston Pin

    31) Inspection of Piston Pin 1. Measure the piston pin outer diameter. Replace the piston pin if less than the specified value. Piston Pin Outer Diameter: Standard Value 14.00 mm (0.6612 in) Functional Limit: 13.97 mm (0.5500 in) 2. Measure the piston pin hole inner diameter a. Replace the piston if greater than the specified value.

  • Page 192: Inspection Of Crankshaft

    Power Unit 34) Inspection of Crankshaft 1. Measure the crankshaft journal outer diameters a and crank pin outer diameters b. Replace the crankshaft if less than the specified limit. Crankshaft Journal Outer Diameter a: Standard Value 29.988 – 29.996 mm (1.1806 – 1.1809 in) Crank Pin Outer Diameter b: Standard Value 26.972 –...

  • Page 193: Inspection Of Crank Pin Oil Clearance

    35) Inspection of Crank Pin Oil Clearance 1. Clean the connecting rod and metal bearings. Re-install the metal bearings. 2. Place cylinder block upside down on the work bench. Install the piston to the connecting rod 1 and install this assembly to the cylinder block.

  • Page 194: Inspection Of Crankshaft Main Journal Oil Clearance

    Power Unit 36) Inspection of Crankshaft Main Journal Oil Clearance 1. Clean the bearings, crankshaft main journals, and bearing mounting surfaces of the crankcase and cylinder block. 2. Place the cylinder block on a workbench with the cylinder head side facing downward. 3.

  • Page 195: Inner Diameter Of Cylinder/Crankcase Bearing Holder (Inner Diameter Codes)

    8. Loosen bolts in reverse order in several steps. Remove the crankcase and measure the width of the crushed Plastigauge on each main journal. Replace the bearings if greater than the specified limit. Crankshaft Main Journal Oil Clearance: 0.012 – 0.044 mm (0.00047 – 0.00173 in) Functional Limit: 0.060 mm (0.00236 in) If the clearance is less than the specified value,...

  • Page 196: Installation Of Piston And Connecting Rod

    Power Unit 39) Installation of Piston and Connecting Rod 1. Install the connecting rod 2, piston pin 3 and piston pin clips 4 in the piston 1. 4st OIL • Point "3V1-UP" mark a on the connecting rod and "UP" mark b on the piston in the same direction.
  • Page 197 7. Set the piston1 into the piston slider 6 with the "UP" mark on the piston on the flywheel side f, and install it in the cylinder. • Before installing, apply engine oil to piston peripheral surfaces, piston rings and piston sliders.
  • Page 198 Power Unit 13. Degrease the bearing holder surface of the crankcase and the bearing contact surface, and install one side of the bearing in the crankcase. • Be sure to install the individual bearings at their original locations. • Install the bearings with their protrusions fitted into the crankcase grooves.
  • Page 199 18. Install the oil pressure switch lead wire r. • Apply ThreeBond 1327 on to thread of oil pressure switch, before installation. • Use 24 mm Socket wrench. Oil Pressure Switch: 8 N · m (6 lb · ft) [0.8 kgf · m] 19.

  • Page 200: Assembling Electrical System And Fuel System Parts

    Power Unit 40) Assembling Electrical System and Fuel system Parts 1. Install the oil level gauge guide 1. • The O-ring cannot be reused. • Apply 4-stroke engine oil on the O-ring. 2. Remove the engine temperature sensor 2. Engine temperature Sensor: 4 N ·...
  • Page 201 6. Install the fuel rail 6. Apply a screw locking agent (ThreeBond 1342) to the thread area of the bolt. • Apply 4-stroke engine oil on the seal ring. 7. Install the fuel pump 7. Apply 4-stroke engine oil to the cam unit and O-ring of the fuel pump.
  • Page 202 Power Unit 11. Install the ignition coil q and attach the plug caps to the spark plugs. 12. Install the ground wire w (rectifier, ignition coil). • Secure the rectifier lead wire and rectifier ground wire with clamp a. • Route the engine temperature sensor lead wire along the ignition coil ground wire.
  • Page 203 16. Install the starter motor p. Route the fuse lead wire and main harness behind the starter motor. 17. Install the throttle body a. Arrange the main harness, TPS coupler, and ISC coupler behind the throttle body. 18. Install the intake silencer s, ISC valve hose d, and breather hose f.
  • Page 204 Power Unit 21. Install the alternator ;. Route the alternator lead wire through the hole behind the starter motor. 22. Connect the alternator connector to the main harness and rectifier lead wire, then install the protector z. 23. Install the flywheel. Flywheel Nut: 58 N ·...

  • Page 205: Installation Of Oil Strainer

    41) Installation of Oil Strainer 1. Install the oil strainer 1 and the plunger 2. Tightening Torque: Plunger 30 N•m (22 lb•ft) [3.0 kgf•m] • Place the power unit ass'y 3 on the work bench with the port side down and install the oil strainer •...
  • Page 206 Power Unit 4. Install the drive shaft housing cover 4 and screws 5. 5. Install the cooling water hose 6. 6. Install the starter lock cable 7 and tighten the screw 8. 7. Install the bracket 9 and throttle drum 0. 8.
  • Page 207 9. Install the fuel hose (IN) e. 10. Connect the connectors for the indicator lamp, stop switch, neutral switch, start switch, fuse, and PT switch. • Connect the start switch and fuse connectors for the electric start model only. • Connect the PT switch connector for the power tilt model only.

  • Page 208: Adjustment Of Starter Lock Cable

    Power Unit 43) Adjustment of Starter Lock Cable 1. Shift the gear into neutral (N). 2. Check that the starter lock lever 1 is pushing up the starter lock 2. 3. If the state described in 2. does not exist, perform adjustment using the starter lock wire adjusting groove a.

  • Page 209: Inspection Of Recoil Starter

    1 1 342 1342 1342 5. Remove the starter shaft bolt 4, friction plate 3, friction spring 2, ratchet, and return spring. 6. Take out the reel carefully. 2 Friction Spring 3 Friction Plate 4 Starter Shaft Bolt 7. Remove the starter spring q. Insert a flathead screwdriver or similar tool and slowly remove the starter spring along with it.
  • Page 210 Power Unit ● When installing the starter spring and case onto the starter reel, align the outer hook a of the starter spring with the round protrusion c on the starter reel. ● Pass the starter rope through the rope guide. ●...
  • Page 211 Lower Unit 1. Special Tools ………………………………… 6-2 17) Disassembly of Propeller Shaft Housing … 6-15 2. Parts Layout …………………………………… 6-4 18) Inspection of Propeller Shaft Housing …… 6-16 Drive Shaft Housing ……………………………… 6-4 19) Assembly of Propeller Shaft Housing ……… 6-16 Gear Case ……………………………………………………...

  • Page 212: Lower Unit

    Lower Unit 1. Special Tools Spring Pin Tool A (ø3.0) Spring Pin Tool B (ø3.0) Spring Pin Tool A (ø3.5) Spring Pin Tool B (ø3.5) P/N. 345-72228-0 P/N. 345-72227-0 P/N. 369-72227-0 P/N. 369-72228-0 Removing spring pin Installing spring pin Removing spring pin Installing spring pin ø27.5 x ø15.5 Driver Rod...
  • Page 213 4st 6/8/9.9 2024...

  • Page 214: Parts Layout

    Lower Unit 2. Parts Layout Drive Shaft Housing 24 N·m (18 lb·ft) [2.4 kgf·m] 1 15 N·m (11 lb·ft) [1.5 kgf·m] 2 30 N·m (22 lb·ft) [3.0 kgf·m] 1342 1 1 342 1342 4st OIL 11.5 N·m (8.5 lb·ft) [1.2 kgf·m] 4st 6/8/9.9 2024...
  • Page 215 Ref. Part Name Q'ty Remarks Drive Shaft Housing Assy (S) Drive Shaft Housing Assy (L) Oil Seal 12-28-5 Do not reuse. Drain Bolt Washer 14.5-24-1 Dowel Pin 6-12 Grommet Flushing Connector Cap Seal Ring Do not reuse. Idle Exhaust Port Cover Idle Exhaust Port Gasket Do not reuse.

  • Page 216: Gear Case

    Lower Unit Gear Case 6 N·m (4 lb·ft) [0.6 kgf·m] 1342 1 1 342 1342 GEAR GEAR GEAR GEAR 4st OIL 11.5 N·m (8.5 lb·ft) [1.2 kgf·m] 62 63 4 N·m (3 lb·ft) [0.4 kgf·m] 12 N·m (9 lb·ft) [1.2 kgf·m] 4st 6/8/9.9 2024...
  • Page 217 Ref. Part Name Q'ty Remarks Gear Case Assy Roller Bearing 15-21-16 Ball Bearing 6204 Do not reuse. Plug 8-8 Gasket 8.1-15-1 Do not reuse. Trim Tab Bolt Water Strainer W = 17 Mark A Screw Nylon Nut 4-P0.7 Propeller Shaft Housing Assy O-ring 3.2-47 Do not reuse.
  • Page 218 Lower Unit 6 N·m (4 lb·ft) [0.6 kgf·m] 1342 1 1 342 1342 GEAR GEAR GEAR GEAR 4st OIL 11.5 N·m (8.5 lb·ft) [1.2 kgf·m] 62 63 4 N·m (3 lb·ft) [0.4 kgf·m] 12 N·m (9 lb·ft) [1.2 kgf·m] 4st 6/8/9.9 2024...
  • Page 219 Ref. Part Name Q'ty Remarks Cam Rod Bushing O-ring A 2.5-4.9 Do not reuse. O-ring 2.4-15.4 Do not reuse. Stopper Cam Rod Bushing Bolt Bolt 6-35 Water Seal Rubber Water Seal Plate Water Pipe (S) Transom S Water Pipe (L) Transom L Water Pipe (UL) Transom UL...

  • Page 220: Inspection Items

    Lower Unit 3. Inspection Items 1) Draining Gear Oil 1. Drain the gear oil. Refer to “Replacement of Gear Oil” in Chapter 3 2) Removal of Propeller WARNING • Before removing or installing the propeller, be sure to disconnect the battery cables from the battery and remove the stop switch lock plate.

  • Page 221: Removal Of Lower Unit

    3) Removal of Lower Unit WARNING When working with the outboard motor in the tilt- up position, be sure to lock it with the tilt stopper. • Removal of the lower unit does not require the power unit to be removed from the outboard motor.

  • Page 222: Inspection Of Water Pump

    Lower Unit 5) Inspection of Water Pump 1. Check the pump case (upper) 1 for deformation. Replace if necessary. 2. Check the impeller 2 and pump case liner 3 for any cracks and wear. Replace if necessary. 3. Check the pin 4, water pump guide plate 5, and drive shaft recess a for wear.

  • Page 223: Disassembly Of Clutch Cam And Cam Rod

    7) Disassembly of Clutch Cam and Cam Rod 1. Remove the spring pins 2 from the cam rod 1, and remove the clutch cam 3 and cam rod bushing. • Use the spring pin tool A to remove the spring pins.

  • Page 224: Assembly Of Pump Case (Lower)

    Lower Unit 12) Assembly of Pump Case (Lower) 1. Apply gear oil to the oil seal attachment surface and press- fit until abutted using an appropriate mandrel. 2. Apply lithium grease to the lip of the oil seal. With reference to the illustration, install the oil seal with the side a having a wide outer circumference facing the coolant side and the side b having a narrow outer circumference...

  • Page 225: Inspection Of Propeller Shaft

    15) Inspection of Propeller Shaft 1. Check the propeller shaft for bends and wear. Replace if necessary. 2. Measure the propeller shaft runout. Runout Limit: 0.05 mm (0.0020 in) a Support points 16) Assembly of Propeller Shaft Assy 1. Fix the propeller shaft with a vice, and install the spring 5 and clutch 4.

  • Page 226: Inspection Of Propeller Shaft Housing

    Lower Unit 2. Use a commercially available universal puller plate to remove the ball bearing. Before removal, check the bearing for play or deflection. Replace if necessary. CAUTION Do not reuse a removed bearing. 3. To remove the oil seal only, use a flathead screwdriver or similar tool.

  • Page 227: Removal Of Drive Shaft

    2. Apply gear oil to the attachment surface of the bearing and press-fit using an appropriate mandrel 3 until abutted. I n s t a l l t h e b a l l b e a r i n g 4 w i t h t h e GEAR GEAR GEAR...
  • Page 228 Lower Unit 2. Using a press, remove the ball bearing 1 in the direction of the bevel gear B along with the spacers and the like. 3. Attach the ball bearing 1 to the drive shaft 2 by press- fitting using a press until dimension a is reached. Attach the ball bearing 1, washer 3, spacer 4, and roller bearing inner ring 5, in this order.

  • Page 229: Removal Of Bevel Gear Assy A And Bearing

    22) Removal of Bevel Gear Assy A and Bearing 1. Apply a rag to a flathead screwdriver or similar object and press against the bushing inner surface of the bevel gear assy A to pull it out. • When removing the bevel gear assy A, be careful not to damage or lose the shim between the gear and ball bearing.

  • Page 230: Disassembly Of Gear Case

    Lower Unit 24) Disassembly of Gear Case 1. Use the tools below to remove the roller bearing 1. Roller Bearing Press Kit: P/N. 3AC-72900-3 Bearing Outer Press Guide 2: Roller Bearing Press Rod 3: Roller Bearing Press 4: 0-Ring 5: Roller Bearing Press Bolt 6: Bolt M8-110 7: Collar 8:...

  • Page 231: Assembly Of Gear Case

    26) Assembly of Gear Case When replacing a ball bearing, gear, drive shaft, propeller shaft, or gear case , make shim adjustments. 1. Install the roller bearing 1 using the tools below. Roller Bearing Press Kit: P/N. 3AC-72900-3 Bearing Outer Press Guide 2: Roller Bearing Press Rod 3: Roller Bearing Press 4: 0-Ring 5:...
  • Page 232 Lower Unit 2. Use the tools below to install the ball bearing. Bearing Outer Press Kit: P/N. 3B7-72739-1 Bearing Outer Press Plate 1: Bearing Outer Press Guide 2: Bearing Outer Press Rod 3: 3. Fix the gear case horizontally in a vice or other holder with its propeller shaft opening facing upward.

  • Page 233: Installation Of Bevel Gear Assy A

    27) Installation of Bevel Gear Assy A 1. In the gear case, install the bezel gear assy A 1 and the shim 2 to the ball bearing using the propeller shaft. 28) Installation of Bevel Gear B 1. Lift the drive shaft assy 1 slightly upward and install the bezel gear B2.
  • Page 234 Lower Unit 29) Backlash Measurement and Shim Selection Backlash Measuring Tool Kit: P/N. 369-72740-0 Backlash Measuring Tool Assy1: Measuring Tool Set Piece 2: Backlash Measuring Tool Clamp A3: P/N. 3B7-72720-0 Dial Gauge Plate 4: P/N. 3B7-72729-0 5 Pump Case (Lower) 6 Bevel Gear B 1.
  • Page 235 2. First, pull up the drive shaft by hand. Fix the shaft B with a flathead screwdriver and tighten the nut while pressing. Be careful not to over-tighten the shaft B 90° at this time, otherwise the shaft B will not move. Tighten the nut with your finger, and then further tighten it with a wrench to about 90°...

  • Page 236: Installation Of Propeller Shaft Housing

    Lower Unit 5. After adjustment, remove the backlash measuring tool, invert the gear case, and turn the drive shaft slowly to see if it turns smoothly. If not, reduce the shim thickness by 0.05 mm and adjust the backlash again. •...

  • Page 237: Installation Of Water Pump

    31) Installation of Pump Case 1. Remove the pump case (lower) and (upper) and apply lithium grease to the lip of the oil seal. 2. Install a new gasket 1 and the pump case (lower) 2. Before installation, clean the drive shaft using a new rag.
  • Page 238 Lower Unit 4. Install the pump case liner 5 to the pump case (upper) 6 and apply OBM grease to the inside of the pump case liner Align the protruding portion a of the pump case liner with the groove b of the pump case (upper).

  • Page 239: Installation Of Lower Unit

    6. Fill with the specified amount a of gear oil. Refer to Chapter 3. GEAR Carry out the task “Inspection of Gear Case (for leakage)” in Chapter 3 as necessary. Gear OIL GEAR GEAR GEAR 33) Installation of Lower Unit WARNING When working with the outboard motor in the tilt- up position, be sure to lock it with the tilt stopper.
  • Page 240 Lower Unit 2. Shift the gear on the engine side and on the gear case side into neutral (N). 3. Connect the shift rod and cam rod using a new spring pin. Spring Pin Tool B (ø3.0) 2: P/N. 345-72228-0 Install the spring pin so that the abutment opening is vertically oriented.
  • Page 241 Bracket 1. Parts Layout…………………………………… 7-2 3. Parts Layout (PT model) …………………… 7-38 Drive Shaft Housing …………………………………… 7-2 Bracket (EFT & EPT models) ……………………… 7-38 Clamp Bracket (MF & EF models) ……………… 7-4 Power Tilt Assy …………………………………………… 7-42 Clamp Bracket (EP model) ………………………… 7-8 4.

  • Page 242: Parts Layout

    Bracket 1. Parts Layout Drive Shaft Housing 24 N·m (18 lb·ft) [2.4 kgf·m] 1 15 N·m (11 lb·ft) [1.5 kgf·m] 2 30 N·m (22 lb·ft) [3.0 kgf·m] 1342 11.5 N·m (8.5 lb·ft) [1.2 kgf·m] 1 1 342 1342 4st OIL 4st 6/8/9.9 2024...
  • Page 243 Ref. Part Name Q'ty Remarks Drive Shaft Housing Assy (S) Drive Shaft Housing Assy (L) Oil Seal 12-28-5 Do not reuse. Drain Bolt Washer 14.5-24-1 Dowel Pin 6-12 Grommet Flushing Connector Cap Seal Ring Do not reuse. Idle Exhaust Port Cover Idle Exhaust Port Gasket Do not reuse.
  • Page 244 Bracket Clamp Bracket (MF & EF models) 9 N·m (7 lb·ft) [0.9 kgf·m] 13 N·m (9 lb·ft) [1.3 kgf·m] 30 35 14 N·m (10 lb·ft) [1.4 kgf·m] 14 N·m (10 lb·ft) [1.4 kgf·m] 3 N·m (2 lb·ft) [0.3 kgf·m] 1342 1 1 342 1342 1530D...
  • Page 245 Ref. Part Name Q'ty Remarks Clamp Bracket (R) MF EF Clamp Bracket (L) MF EF Bolt 8-122 MF EF Nylon Nut 8-P1.25 MF EF Washer MF EF Washer 8.5-28-1 MF EF Bracket Distance Plate MF EF Screw MF EF Stern Bracket Spring MF EF Screw MF EF...
  • Page 246 Bracket 9 N·m (7 lb·ft) [0.9 kgf·m] 13 N·m (9 lb·ft) [1.3 kgf·m] 30 35 14 N·m (10 lb·ft) [1.4 kgf·m] 14 N·m (10 lb·ft) [1.4 kgf·m] 3 N·m (2 lb·ft) [0.3 kgf·m] 1342 1 1 342 1342 1530D 1530D 1530D 1530D 4st 6/8/9.9 2024...
  • Page 247 Ref. Part Name Q'ty Remarks Rubber Mount (Lower) Mount Bracket (R) Mount Bracket (L) Bolt Ground L = 110 Ground L = 110 Bolt Tilt Stopper Assy MF EF *Tilt Stopper Grip MF EF Tilt Stopper Bushing MF EF Tilt Stopper Setting Plate MF EF Bolt MF EF...
  • Page 248 Bracket Clamp Bracket (EP model) 28 N·m (21 lb·ft) [2.8 kgf·m] 25 N·m (18 lb·ft) [2.5 kgf·m] 1342 1 1 342 1342 4st 6/8/9.9 2024...
  • Page 249 Ref. Part Name Q'ty Remarks Clamp Bracket (R) Clamp Bracket (L) Washer 22-36-1 EFT EP EPT Swivel Bracket Grease Fitting EFT EP EPT Reverse Lock Reverse Lock Spring Steering Shaft Assy EP EPT Trim Position Decal Lower Tilt Limit Decal Tilt Lock Decal Distance Piece Bolt...
  • Page 250 Bracket 28 N·m (21 lb·ft) [2.8 kgf·m] 25 N·m (18 lb·ft) [2.5 kgf·m] 1342 1 1 342 1342 7-10 4st 6/8/9.9 2024...
  • Page 251 Ref. Part Name Q'ty Remarks Carrying Handle EP EPT Steering Hook Plate EP EPT Collar 10.1-20-15 EP EPT Bolt EP EPT Washer EP EPT Rigging Bolt Set EP EFT EPT 47-1 *Bolt EF EFT 47-2 *Bolt 48-1 *Washer EF EFT 48-2 *Washer 49-1...
  • Page 252 Bracket Tiller Handle & Shift Lever 8 N·m (6 lb·ft) [0.8 kgf·m] 40 41 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 1342 1 1 342 1342 1373B 1373B 1373B 1373B 7-12 4st 6/8/9.9 2024...
  • Page 253 Ref. Part Name Q'ty Remarks Tiller Handle Assy MF EF *Plastic Rivet 6.5 MF EF EFT *Stud MF EF EFT *Grip MF EF EFT *Throttle Shaft MF EF EFT *Throttle Shaft Damper MF EF EFT *Bushing 14-15.8-7 MF EF EFT *Screw MF EF EFT *Throttle Shaft Support...
  • Page 254 Bracket 8 N·m (6 lb·ft) [0.8 kgf·m] 40 41 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 1342 1 1 342 1342 1373B 1373B 1373B 1373B 7-14 4st 6/8/9.9 2024...
  • Page 255 Ref. Part Name Q'ty Remarks Washer MF EF EFT Shift Decal MF EF EFT 4st 6/8/9.9 2024 7-15...

  • Page 256: Bottom Cowl & Shift

    Bracket Bottom Cowl & Shift 1342 1 1 342 1342 7-16 4st 6/8/9.9 2024...
  • Page 257 Ref. Part Name Q'ty Remarks Bottom Cowl Pilot Lamp Assy Battery Cable Grommet Shift Rod Grommet Shift Rod Grommet Grommet MF EF EFT Cowl Latch Assy Bolt Grommet 17-2.7 MF EP EPT Starter Lock Cable Bracket Bolt Fuel Connector (Male) Bolt EP EPT Fuel Connector Protector...
  • Page 258 Bracket 1342 1 1 342 1342 7-18 4st 6/8/9.9 2024...
  • Page 259 Ref. Part Name Q'ty Remarks Washer 6.5-21-1 EP EPT Shift Lever Rod EP EPT Washer 8.5-18-1.6 EP EPT Snap Pin d = 8 EP EPT Shift Lever Bracket Cover MF EF EFT EP Bolt Grommet MF EF EFT Cable Clip Assy EP EPT Bolt EP EPT...
  • Page 260 Bracket Remote Control Parts Fig.4-2 1342 1342 1342 14 N·m (10 lb·ft) [1.4 kgf·m] 1342 1 1 342 1342 Ref. Ref. Part Name Remarks Part Name Remarks Q'ty Q'ty Grommet for EP 18 Remote Control Cable Stay Cover 19 PTT Switch Assy 2 Grommet for EPT 20 Cable Clip Assy...

  • Page 261: Inspection Items

    2. Inspection Items 1) Inspection of Throttle Cable 1. Check the operation of the throttle cable. 2. Check the throttle cable inner wire and outer wire for bending or damage. Replace if necessary. 2) Installation of Tiller Handle 1. Install the stop switch lead wire 1 and throttle wire to the cover 2 first.
  • Page 262 Bracket 4. Install the bushings 5 to the steering bracket 6. 5. Install the tiller handle assy to the steering bracket 6 and tighten the nut 7 to the specified torque. The tiller handle has a positioning bump. Attach the handle by aligning the bump with the cutout portion of the cover 8.

  • Page 263: Adjustment Of Co-Pilot Plate

    3) Adjustment of Co-pilot Plate (EFT model only) 1. Install the co-pilot plate and tiller handle assy. 2. Move the co-pilot handle to the left and slide it to the tightening position. 3. Tighten the nylon nut 1 until the outboard motor is tightened and heavy.
  • Page 264 Bracket 4) Removal of Drive Shaft Housing 1. With reference to Chapter 5 “Removal of Power Unit,” drain the engine oil completely and remove the power unit. 2. Loosen the the four bolts 1 and remove the bottom cowl from the drive shaft housing. 3.

  • Page 265: Disassembly Of Drive Shaft Housing

    6. Remove the nut of the upper rubber mount 6. 7. Remove the drive shaft housing 7 from the clamp bracket assy. Be careful not to drop the drive shaft housing during removal from the clamp bracket. 5) Disassembly of Drive Shaft Housing 1.
  • Page 266 Bracket 3. Remove the idol exhaust cover 4 and gasket 5, and check the cover and the interior for sludge, cracks, fissures, and other abnormalities. 4. Remove the screw 6 and then remove the water pipe 7 from the drive shaft housing. Check the water pipe auxiliary mount 8 for abnormalities such as fissures and cracks.
  • Page 267 6) Assembly of Drive Shaft Housing 1. Install the water pipe 1 into the drive shaft housing. 2. Install a new gasket and tighten the idle exhaust cover installation bolts in the order illustrated to the specified torque. 1 1 342 1342 1342 Idle Exhaust Installation Bolt :...

  • Page 268: Installation Of Drive Shaft Housing Assy

    Bracket 7) Installation of Drive Shaft Housing Assy 1. Insert the drive shaft housing assy into the stud bolt 3 of the upper rubber mount 2 of the swivel bracket 1. Correctly align the bolt hole position of the damper when installing. 2.

  • Page 269: Removal Of Steering Shaft

    3. Attach the ground wire 7. • Be careful not to coat the ground wire attachment surface. Doing so eliminates the anti-corrosion effect. • If there are two ground wires, separate them by 90° as illustrated. 8) Removal of Steering Shaft 1.

  • Page 270: Installation Of Steering Shaft

    Bracket 9) Installation of Steering Shaft 1. Install the thrust plate 1, bushing 2, and friction piece 3 to the steering shaft. 2. Stand the swivel bracket assy vertically, and insert the steering shaft into the swivel bracket assy. 3. Install the bushing 4, new O-ring 5, and thrust plate 6 to the swivel bracket.
  • Page 271 6. Install the co-pilot handle and adjust the co-pilot. (EFT model) 10) Disassembly of Clamp Bracket (EP model) 1. Remove the drive shaft housing, steering shaft, and co-pilot. 2. Loosen the swivel bracket shaft 1 and nut 2. Loosen the bolt 4 of the distance piece 3, and remove the bolt 4.
  • Page 272 Bracket 11) Installation of Clamp Bracket (EP model) 1. Return the area around the swivel bracket 1 to its original state, and insert and install the distance piece 3 into the clamp bracket 2. 2. Install the clamp brackets onto the swivel bracket, insert the swivel bracket shaft 4, and tighten the nylon nut 5 and bolts 6 to the specified torque.

  • Page 273: Disassembly Of Clamp Bracket (Mf & Ef Models)

    12) Disassembly of Clamp Bracket (MF & EF models) 1. Remove the thrust rod 1 from the clamp bracket 2. 2. Remove the distance plate 3. 3. Loosen and remove the nut 5 of the swivel bracket shaft Pull out the swivel bracket shaft and remove the clamp bracket from the swivel bracket 6.

  • Page 274: Installation Of Clamp Bracket

    Bracket 4. Check the swivel bracket shaft and other par ts for abnormality, and replace if necessary. 13) Installation of Clamp Bracket (MF & EF models) 1. Return the area around the swivel bracket 1 to its original state, and install the distance plate 3 in the clamp bracket 7-34 4st 6/8/9.9 2024...

  • Page 275: Inspection Of Reverse Lock

    2. Install the clamp brackets onto the swivel bracket, insert the swivel bracket shaft 4, and tighten the nylon nut 5 to the specified torque. Nylon Nut 5: 14 N·m (10 lb·ft) [1.4 kgf·m] Apply sufficient OBM grease to the swivel bracket shaft.
  • Page 276 Bracket 4. Check that the reverse lock lowers and tilt-up cannot occur when the shift is in neutral (N) and reverse (R). 7-36 4st 6/8/9.9 2024...
  • Page 277 4st 6/8/9.9 2024 7-37...

  • Page 278: Parts Layout (Pt Model)

    Bracket 3. Parts Layout (PT model) Bracket (EFT & EPT models) 1342 1 1 342 1342 1530D 1530D 1530D 1530D 7-38 4st 6/8/9.9 2024...
  • Page 279 Ref. Part Name Q'ty Remarks Clamp Bracket (PTT-R) EFT EPT Clamp Bracket (PTT-L) EFT EPT Co-Pilot Decal Trim Lock Pin EFT EPT Washer 8.1-16-1.5 EFT EPT Nylon Nut 8-P1.25 EFT EPT Bolt EFT EPT Bolt EFT EPT Swivel Bracket Assy EFT EPT Tilt Stopper (PTT) EFT EPT...
  • Page 280 Bracket 1342 1 1 342 1342 1530D 1530D 1530D 1530D 7-40 4st 6/8/9.9 2024...
  • Page 281 Ref. Part Name Q'ty Remarks Bolt EFT EPT Washer 6.5-23-1.5 EFT EPT Cylinder Pin (Lower) EFT EPT Bolt EFT EPT Lead Wire Band 203 EFT EPT Do not reuse. Washer 8.5-28-1 EFT EPT Friction Lever Bushing 24-30-30 EFT EPT Bushing 24-30-30 EFT EPT Anode EFT EPT...

  • Page 282: Power Tilt Assy

    Bracket Power Tilt Assy 5 N·m (4 lb·ft) [0.5 kgf·m] 1.5 N·m (1.1 lb·ft) [0.15 kgf·m] 2 N·m (1.5 lb·ft) [0.2 kgf·m] 5 N·m (4 lb·ft) [0.5 kgf·m] Ref. Ref. Part Name Remarks Part Name Remarks Q'ty Q'ty Cap Assy 18 O-ring 2-62.5 Do not reuse.

  • Page 283: Power Tilt Functions

    4. Power Tilt Functions • The power tilt system has an electric motor built into the system that drives the hydraulic pump to feed pressurized oil into the tilt cylinder. • The power tilt switch located on the tiller handle or remote control box is used to tilt up or down the outboard motor. 5.

  • Page 284: Tilt Up Operation

    Bracket Tilt Up Operation Pressing the "UP" side of the PT switch rotates the motor (gear of gear pump) rightward. The check valve A opens, and oil flows from the reservoir toward the gear pump and spool valve. This oil flow shifts the spool valve downward, opening the down-pressure main check valve.

  • Page 285: Tilt Down Operation

    Tilt Down Operation Pressing the "DOWN” side of the PT switch rotates the motor (gear pump) leftward. The check valve B opens, and oil flows from the reservoir toward the gear pump and spool valve. This oil flow shifts the spool valve upward to open the up-pressure main check valve.

  • Page 286: Shock Absorber Valve

    Bracket Shock Absorber Valve The PT unit is provided with a shock absorber that protects the drive unit from impact in the event the drive unit hits an underwater obstacle during cruising. When the drive unit hits an underwater obstacle, the hydraulic pressure in the cylinder upper chamber is abruptly increased. This high pressure opens the shock valve of the piston.

  • Page 287: Thermal Valve

    Tilt rod Piston Cylinder lower chamber Thermal valve Thermal Valve The thermal valve protects the drive unit from excessive force that attempts to push down the tilt rod when the outboard motor is in the full tilt-up position. When excessive force is applied, the piston rod is pressed into the cylinder, increasing the hydraulic pressure in the cylinder lower chamber over a rated value.

  • Page 288: Removal Of Pt Unit

    Bracket 6. Removal of PT Unit 1. Fully tilt up the outboard motor and support it with the tilt stopper 1. WARNING • As the hydraulic pressure of the PT unit lowers, the outboard motor may suddenly fall, which is dangerous. Be sure to support the outboard motor with a stopper when tilting the motor up.
  • Page 289 3. Remove the bolt 5 and washer 6 on the starboard side, and remove the upper cylinder pin 7. T h e up p e r c y lin de r pin c a n b e r e m o v e d easily when the tilt rod is retracted a little by performing the tilt down operation.

  • Page 290: Removal And Inspection Of Manual Valve

    Bracket 7. Removal and Inspection of Manual Valve 1. Slowly loosen and remove the PT fill cap 1. Fully extend the tilt rod before removing the fill cap. 2. Drain the PT fluid from the filler cap outlet. 3. Remove the manual valve C-clip 2, and turn the manual valve 3 counterclockwise for removal.

  • Page 291: Motor

    6. Install two O-rings (two locations) 4 in the manual valve. 7. Install the manual valve 3 in the PT assy. 8. Install the C-ring 2. 8. PT Motor 1) Removal, Inspection, and Repair of PT Motor 1. Remove two inner hex bolts 1, and remove the motor assy 2 from the PT pump and cylinder assy 2.

  • Page 292: Continuity Test

    Bracket 2) Continuity Test 1. Check the conductivity of the armature 2. Replace the armature assy if the conductivity is other than the specification. Armature Conductivity: 3 Commutator Non-conductive 4 Armature shaft 1 Meter 2 Armature 3 Commutator 4 Armature Assy 3) Inspection of Motor 1 1 1 1.

  • Page 293: Assembly Of Pt Motor

    5) Assembly of PT Motor 1. Attach the breaker 7 to the motor bracket 8. 2. Attach the circuit breaker holder securely using screws. 3. Attach the blue wire 1 to the terminal post of the breaker 4. Arrange the green wire 2 along the inner diameter area of the bracket.

  • Page 294: Pump

    Bracket 11. Attach the yoke assy 1 securely using the the two screws 1 Yoke Assy 2 Screw (2) 3 Motor Bracket 9. PT Pump 1) Disassembly of PT Pump WARNING Contamination of the hydraulic system can result in damage to the components and circuits, possibly resulting in serious damage to the product.
  • Page 295 5. Remove the three screws 2 and 3 holding the PT pump 1 and the assembly together. 1 PT Pump 2 Internal Hex Screw (5 mm × 20) 3 Internal Hex Screw (5 mm × 25) 6. Remove the up-side relief valve 1, down-side relief orifice 2, and then the O-ring 3 from the PT housing.

  • Page 296: Assembly Of Pt Pump

    Bracket 2) Assembly of PT Pump 1. Apply oil to the new O-rings (two locations) q and attach them in the PT housing. 2. Apply oil to the new O-ring 9 and install it in the orifice 3. Attach the filter 8 and the orifice 0. 4.
  • Page 297 6. Attach the cleaned screen 1. 7. Attach the pump coupling 2 to the pump. 8. Install the motor assy to the PT pump and cylinder assy. 9. Attach the wire harness mounting screws. 1 Pump Filter 2 Pump/Motor Coupler 10.

  • Page 298: Air-Purging Pt Unit (Separated From Outboard Motor)

    Bracket 3) Air-Purging PT Unit (Separated from Outboard Motor) 1. Turn the manual valve 1 clockwise (to the right) until it no longer turns. 2. Set the PT unit 2 vertically, remove the cap 3, and check the fluid level in the reserve. WARNING Check the fluid level with the tilt rod fully extended.

  • Page 299: Installation Of Pt Assy

    4) Installation of PT Assy 1. Fully tilt up the outboard motor and support it with the tilt stopper 1. WARNING • Be sure to lock the outboard motor with the tilt stopper after tilting it up. Leaving the outboard motor up without locking may lead to accidental descent due to the reduction of PT unit hydraulic pressure, which is dangerous.
  • Page 300 Bracket 7. Attach the washer 9 and bolt 0 to the pin (lower) 8 and tighten to the specified torque. Retaining bolt : 13 N·m (1.9 lb·ft) [1.3 kgf·m] 8. Install the bushings (2 locations) e to the swivel bracket w. 9.

  • Page 301: Inspection Of Pt Solenoid

    13. Attach the PT electrical cord to the PT solenoid terminals y and o. y Down Relay Terminal (Green) u － Electrode Terminal (Black) i ＋ Electrode Terminal (Red) o Up Relay Terminal (Blue) 14. Unlock the tilt stopper, and repeat tilting the outboard motor up and down to bleed air from the hydraulic circuit.

  • Page 302: Inspection Of Pt Switch

    Bracket Bracket Inspection of UP side solenoid 4. As shown in the figure, connect the blue (L) terminal in the coupler to the battery positive terminal and the black (B) terminal (B) to the negative terminal, then connect the circuit tester leads to the PT solenoid terminals 1 and 3. 5.
  • Page 303 Electrical System 1. Special Tools ………………………………… 8-2 10) Inspection of the Main Switch Assy (EF, EFT) 8-23 2. Electrical Component Layout …………… 8-3 11) Inspection of the Main Switch Assy (Key) … 8-23 Port Side View ………………………………………… 8-3 12) Inspection of the Stop Switch Assy ………… 8-24 Bow Side View …………………………………………...

  • Page 304: Electrical System

    Electrical System 1. Special Tools Vacuum/Pressure Gauge Spark Tester P/N. 3AC-99020-1 P/N. 3F3-72540-0 Inspecting pressure Inspecting ignition 4st 6/8/9.9 2024...
  • Page 305 2. Electrical Component Layout Port Side View 1 Oil Pressure Switch 2 Ignition Coil 3 Engine TEMP Sensor 4 Rectifier Complete (except for MF model) 5 Starter Motor Assy (except for MF model) 4st 6/8/9.9 2024...

  • Page 306: Bow Side View

    Electrical System Bow Side View 1 ECU/charge coil (charge coil except for MF model) 2 Pulser Coil 3 Starter Solenoid Switch (except for MF model) 4 Fuse (20A) (except for MF model) 5 Neutral Switch (except for MF model) 6 PTT Solenoid Switch (B) (DOWN side) (EFT, EPT models) 7 PTT Solenoid Switch (A) (UP Side) (EFT, EPT models) 4st 6/8/9.9 2024...

  • Page 307: Starboard Side View

    Starboard Side View 1 Fuel injector 2 T- MAP Sensor 3 Throttle Position Sensor 4 ISC Valve 5 ECU Assy 6 Vapor Separator Assy 4st 6/8/9.9 2024...

  • Page 308: Housing Cover (Front)

    Electrical System Housing Cover (Front) 1 Pilot Lamp Assy 2 Main Switch Assy (EF, EFT models) 3 Stop Switch Assy 4 PT Switch (EFT model) 4st 6/8/9.9 2024...
  • Page 309 4st 6/8/9.9 2024...

  • Page 310: Parts Layout

    Electrical System 3. Parts Layout Magneto & Electric Parts 58 N·m (43 lb·ft) [5.8 kgf·m] 4 N·m (3 lb·ft) [0.4 kgf·m] 8 N·m (6 lb·ft) [0.8 kgf·m] 25 26 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 2.7 N·m (2.0 lb·ft) [0.27 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m]...
  • Page 311 Ref. Part Name Q'ty Remarks Flywheel Assy Alternator Assy Pulser Coil Key 13.4-5-4 Nut 12-P1.25 Washer Bolt Bolt Electrical Bracket Collar Bolt ECU Assy (9.8) ECU Holder Cord Assy Grommet Oil Pressure Switch Cable Terminal Plug Diagnostic Connector Cap Cable Terminal Plug Rubber Mount Protector Band...
  • Page 312 Electrical System 58 N·m (43 lb·ft) [5.8 kgf·m] 4 N·m (3 lb·ft) [0.4 kgf·m] 8 N·m (6 lb·ft) [0.8 kgf·m] 25 26 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 2.7 N·m (2.0 lb·ft) [0.27 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m] 3.5 N·m (2.5 lb·ft) [0.35 kgf·m]...
  • Page 313 Ref. Part Name Q'ty Remarks Bolt EF EFT EP EPT Terminal Cap EF EFT EP EPT Terminal Cap EF EFT EP EPT Terminal Cap EF EFT EP EPT Starter Cable L = 200 EF EFT EP EPT Neutral Switch Bracket EF EFT EP EPT Neutral Switch EF EFT EP EPT...

  • Page 314: Intake Manifold & Fuel Pump

    Electrical System Intake Manifold & Fuel Pump 4st OIL 4 N·m (3 lb·ft) [0.4 kgf·m] 5 N·m (3.7 lb·ft) [0.5 kgf·m] 1342 1 1 342 1342 8-12 4st 6/8/9.9 2024...
  • Page 315 Ref. Part Name Q'ty Remarks Fuel Rail Assy * Fuel Rail * Fuel Injector Assy * Seal Ring Do not reuse. * Valve Assy (Pressure Check) * Valve Cap * Nipple Bolt Insulator Band Do not reuse. Vapor Separator Assy * Cover * Seal Do not reuse.
  • Page 316 Electrical System 4st OIL 4 N·m (3 lb·ft) [0.4 kgf·m] 5 N·m (3.7 lb·ft) [0.5 kgf·m] 1342 1 1 342 1342 8-14 4st 6/8/9.9 2024...
  • Page 317 Ref. Part Name Q'ty Remarks Fuel Pump Assy O-ring Do not reuse. Screw Hose Clip ø9.4 Clip ø9.4 Hose Fuel Filter Assy * Cup * Filter * O-ring Do not reuse. * O-ring Do not reuse. * Drain Valve * Seal Do not reuse.
  • Page 318 Electrical System 4st OIL 4 N·m (3 lb·ft) [0.4 kgf·m] 5 N·m (3.7 lb·ft) [0.5 kgf·m] 1342 1 1 342 1342 8-16 4st 6/8/9.9 2024...
  • Page 319 Ref. Part Name Q'ty Remarks Collar Washer 6-16-1.5 Bolt Throttle Rod Breather Hose Fuel Hose W/Protector Restrictor Water Nipple Hose Clip ø9.4 Clamp 6.5-14L Bolt Throttle Drum Assy Throttle Wire Bracket Bolt Band Do not reuse. MF EF EFT 4st 6/8/9.9 2024 8-17...

  • Page 320: The Ignition System And The Ignition Control System

    Electrical System 4. The Ignition System and the Ignition Control System 1) Inspection of the Ignition Spark WARNING • When testing, install the electrode cap properly so as to prevent leaks and contact with the wiring of the spark tester, and perform the test carefully. •...

  • Page 321: Inspection Of The Ignition Coil

    3) Inspection of the Ignition Coil 1. Disconnect the ignition coil. 2. Measure the ignition coil resistance. Replace if other than the specified value. This test can be conducted without removing the part. Ignition Coil Resistance: Primary Coil : Between Black (B) - Orange (Or) 0.26 - 0.35 kΩ...

  • Page 322: Inspection Of The Pulser Coil

    Electrical System 5) Inspection of the Pulser Coil 1. Disconnect the coupler 1 of the pulser coil. 2. Measure the resistance of the pulser coil. Replace if other than the specified value. This test can be conducted without removing the part.

  • Page 323: Inspection Of The Oil Pressure Switch

    7) Inspection of the Oil Pressure Switch Remove the part to test it as a separate unit. 1. Remove the oil pressure switch 1. 2. Check the conductivity of the oil pressure switch. Replace it if it is not conductive. 3.

  • Page 324: Inspection Of The Engine Temperature Sensor

    Electrical System 8) Inspection of the Engine Temperature Sensor Remove the part to test it as a separate unit. 1. Remove the engine temperature sensor 1 from the engine. 2. Place the engine temperature sensor in a vessel containing water and slowly heat the water. To measure the resistance at low temperatures, place the sensor in ice water, refrigerator, etc.

  • Page 325: Inspection Of The Main Switch Assy (Ef, Eft)

    10) Inspection of the Main Switch Assy (EF, EFT) 1. Check the conductivity of the main switch assy and replace it if it is not conductive. This test can be conducted without removing the part. Lead Wire Color Switch Position Green (G) Red (R) Free: OFF...

  • Page 326: Inspection Of The Stop Switch Assy

    Electrical System 12) Inspection of the Stop Switch Assy 1. Check the conductivity of the stop switch assy and replace it if it is not conductive. Lead Wire Color Switch Position Brown (Br) Black (B) Remove lock a Install lock b Press switch c 8-24 4st 6/8/9.9 2024...

  • Page 327: The Fuel Control System

    5. The Fuel Control System 1) Inspection of the Injector 1. Measure the injector resistance. • This test can be conducted without removing the part. • The injector operation test can be conducted using the “Engine Shut-down Test” or “Engine Running Test”...

  • Page 328: Inspection Of The T-Map Sensor

    Electrical System 3) Inspection of the T-MAP Sensor The MAP (manifold pressure) sensor and MAT (intake air temperature) sensor are integrated in this sensor. Inspection of the MAT Sensor 1. Measure the ambient temperature. 2. Connect a computer to the outboard motor and use the diagnosis system to display "Air Temperature (Intake Air Temperature)."...

  • Page 329: Inspection Of The Throttle Position Sensor (Tps)

    5) Inspection of the Throttle Position Sensor (TPS) 1. Check the throttle position sensor resistance. Replace the entire throttle body if the value is not as specified. Resistance Between Terminals: 3.5 - 6.5 kΩ 2. Apply a voltage of 5 V between Vta 1 and E2 2 and check the change in voltage between 3 and Vc 3.

  • Page 330: Disassembly Of The Starter Motor Assy

    Electrical System 3) Disassembly of the Starter Motor Assy 1. Mark the starter motor body and the cap with a locating mark (for ease of reassembly). 2. Slide the pinion stopper 1 downward as shown and remove the clip 2. Use a small flathead screwdriver to remove the clutch.

  • Page 331: Inspection Of The Brush

    2. Measure the outer diameter of the commutator 1. Replace the starter motor assy if the value is below the specified value. Commutator Outer Diameter: Standard Value 19.9 - 20 mm (0.783 - 0.787 in) Wear Limit: 19.8 mm (0.780 in) 3.

  • Page 332: Operation Test Of Starter Motor Assy

    Electrical System 7) Operation Test of Starter Motor Assy 1. Assemble the starter motor assy and, before and after installing it in the power unit, apply an electric current between the positive and negative points to confirm that it is working normally. Be careful of fire, because the operating test generates sparks.

  • Page 333: Ecu Coupler

    • Measurement conditions Circuit tester to be used: HIOKI3030 • Range to be used: 1kΩ • Permissible error of resistance is ±20% Note) 1 HIOKI HiTESTER MODEL 3030 was used for this measurement. Using another tester can result in an abnormal resistance value and an inaccurate test.
  • Page 334 Electrical System 8-32 4st 6/8/9.9 2024...
  • Page 335 Troubleshooting 1. Troubleshooting List ………………………… 9-2 State 3 Engine rotation is unstable or hunting occurs in low speed range. ……… 9-14 Power Unit …………………………………… 9-3 Ignition System ……………………………………… 9-15 State 1 Engine will not start or is hard to start. ……………………………… 9-3 Fuel System …………………………………………...

  • Page 336: Troubleshooting List

    Troubleshooting Troubleshooting 1. Troubleshooting List * Low speed ESG is activated Probable Cause ○ ○ Fuel level is low in the tank. ○ ○ ○ ○ ○ ○ ○ Fuel system connection is incomplete. ○ ○ ○ ○ ○ ○ ○...

  • Page 337: Power Unit

    Before working on the engine, check the installation condition of the hull, rigging, and engine, and make sure the fuel is normal and the battery is fully charged. For mechanical troubleshooting, refer to the relevant troubleshooting section in this chapter. For checking and servicing the outboard motor, refer to the service procedures described in this manual to perform the work safely.
  • Page 338 Troubleshooting Troubleshooting Check electrical conductivity of neutral switch. Conductive? Replace neutral switch. Check start switch or main switch. Replace start switch or Normal? main switch key. Check electrical conductivity of wire harness. Repair or replace wire Conductive? harness. Disassemble starter motor to check.

  • Page 339: Ignition System

    Ignition System Check spark plugs. Clean and adjust spark Normal? plugs, or replace. WARNING • When testing, cover the electrode cap properly so as to prevent Use spark tester to check leaks and contact with the wiring of the spark tester. ignition sparks.
  • Page 340 Troubleshooting Troubleshooting Replace ignition coil. Normal? Check ECU coil (exciter coil) resistance. Normal? Replace alternator. Check ECU. 4st 6/8/9.9 2024...

  • Page 341: Fuel System

    Fuel System Check operation of fuel feed pump (FFP). Check electrical conductivity Operating noise of wire harness. heard? Repair or replace Conductive? defective parts. Check output from ECU to fuel feed pump (FFP). Output signal Check or replace ECU. exists? Replace Measure fuel pressure.
  • Page 342 Troubleshooting Troubleshooting Check mechanical fuel pump. Normal? Replace fuel pump. Check vapor separator needle valve for bend or wear. Normal? Replace needle valve. Check ignition system and compression pressure. 4st 6/8/9.9 2024...

  • Page 343: (Defective Acceleration Or Deceleration)

    Full throttle engine revolution speed is low. Engine revolution speed falls off. Engine stalls. State 2 (Defective acceleration or deceleration) Also check throttle body is fully opened when throttle is fully open. Adjust throttle wire/ Normal? throttle link. Check throttle position sensor and ISC valve connectors for proper connections, and ground lead for looseness.

  • Page 344: Ignition System

    Troubleshooting Troubleshooting Ignition System Check spark plugs. Clean and adjust Normal? spark plug, or replace. WARNING Use spark tester to check • When testing, cover the electrode cap properly so as to prevent ignition sparks. leaks and contact with the wiring of the spark tester. •...

  • Page 345: Fuel System

    Fuel System Measure fuel pressure. Check fuel lter for clogging Speci ed range? and dirt, and piping and fuel rail for leak. Repair or replace Normal? defective parts. Check injector clogging and Replace fuel regulator. resistance. Replace injector. Normal? Check fuel pump. Replace fuel pump.

  • Page 346: Lubrication System

    Troubleshooting Troubleshooting Lubrication System Check engine oil level. Within specified Add engine oil to specified level. range? Check oil pressure switch. Normal? Replace oil pressure switch. Measure hydraulic pressure. Check oil pump for damage Normal? and oil leak. Check ignition system, Clogging or leak? Check oil passage.

  • Page 347: Cooling System

    Cooling System Check cooling water passage for clogging or leak. Clean or replace cooling Normal? water passage. Check thermostat. Normal? Replace thermostat. Measure engine temperature sensor resistance. Replace engine Normal? temperature sensor. Check water pump. Normal? Replace water pump. Check ignition system, fuel system and/or lubrication system.

  • Page 348: State 3 Engine Rotation Is Unstable Or Hunting Occurs In Low Speed Range

    Troubleshooting Troubleshooting State 3 Engine rotation is unstable or hunting occurs in low speed range. Check throttle position sensor and ISC valve connectors for connections and resistances. Repair or replace Normal? defective parts. Check throttle link and throttle valve for play and wear.

  • Page 349: Ignition System

    Ignition System Check spark plugs. Clean and adjust Normal? spark plug or replace. WARNING Use spark tester to check ignition spark. • When testing, cover the electrode cap properly so as to prevent leaks and contact with the wiring of the spark tester. •...

  • Page 350: Fuel System

    Troubleshooting Troubleshooting Fuel System Check fuel filter for clogging and dirt, and piping for leak. Repair, clean or replace Normal? defective parts. Check fuel pump. Normal? Replace fuel pump. Check vapor separator needle valve for bend or wear. Normal? Replace needle valve. Check injector clogging and resistance.

  • Page 351: Unit

    PT Unit State 1 PT unit will not operate. Check operation of PT motor. Operating Check battery and fuse. noise heard? Repair or replace Normal? defective parts. Check electrical conductivity of PT switch. Conductive? Replace PT switch. Check electrical conductivity of PT solenoid.

  • Page 352: State 2 Pt Unit Is Not Capable Of Sustaining The Outboard Motor

    Troubleshooting Troubleshooting Check PT uid level. Within speci ed Add PT uid to speci ed range? level. Disassemble PT unit to check. State 2 PT unit is not capable of sustaining the outboard motor. Check that manual valve is closed. Close manual valve.

  • Page 353: Diagnosis

    Diagnosis An electronically controlled engine can be connected to a PC to diagnose the status of the engine. Information that can b e viewed include self-diag nosis, malfunction records, and status during operation. The operation of individual electronic components of the engine can be viewed to determine the malfunction.
  • Page 354 Troubleshooting 9-20 4st 6/8/9.9 2024...

  • Page 355: Wiring Diagram

    Wiring Diagram Wiring Chart …………………………………… 10-2 MFS8/9.8C EP/EPT (RC12A) MFS8/9.8C MF Electric Circuit ……………… 10-5 Electric Circuit ………………………………… 10-7 MFS8/9.8C EF/EFT Electric Circuit ………… 10-6 MFS8/9.8C EP/EPT (RC12F) Electric Circuit ………………………………… 10-8...

  • Page 356: Wiring Chart

    Wiring Diagram Wiring Chart Name Remarks Lead Wire Color ECU Coil Blue Black/Red Magneto Charge Coil (except for MF model) Yellow White Pulser Coil Red/White Black White Rectifier/Regulator (except for MF model) Yellow Black Starter Motor (except for MF model) Black Black Black...
  • Page 357 Name Remarks Lead Wire Color Red/White 34 Service Connector Diagnosis Port White Yellow Blue Black 35 Resistance Red/White Red/White 36 Fuse Option, 10A Black Black Battery Option Red/White Black 38 Interface Unit Option USB conversion Option 40 Personal Computer Option Electrical Bracket Ground Black...
  • Page 358 Wiring Diagram 10-4 4st 6/8/9.9 2024...
  • Page 359 MFS6CZ/8C/9.8C/9.9CY MF Electric Circuit MAGNETO OPTION CYLINDER BLOCK PULSER COIL FUSE BATTERY REC. /REG. CYLINDER BLOCK DIODE MODULE Starter Motor Solenoid Neutral Switch GROUND SENSOR GROUND INJECTOR POWER +12V FUEL INJECTOR Lg/R ECU SENSOR POWER +5V FUEL INJECTOR Lg/B 24P JOINT CONNECTOR I/G COIL T-MAP SENSOR G/Or...
  • Page 360 MFS6CZ/8C/9.8C/9.9CY EF/ EFT Electric Circuit STARTER MOTOR STARTER MOTOR SOLENOID FUSE MAIN SWITCH NEUTRAL SWITCH PT SOLENOID (UP) CYLINDER MAGNETO BLOCK CYLINDER BLOCK PT SOLENOID (DOWN) PULSER COIL ELECTRIC BRACKET BATTERY PLATE GROUND 3 REC. /REG. ELECTRIC BRACKET CYLINDER BLOCK PLATE GROUND 1 DIODE MODULE #1 PT SWITCH...
  • Page 361 MFS6CZ/8C/9.8C/9.9CY EP/EPT (RC12A) Electric Circuit NEUTRAL SWITCH STARTER MOTOR STARTER MOTOR FUSE SOLENOID PT SOLENOID (UP) CYLINDER MAGNETO BLOCK CYLINDER BLOCK PT SOLENOID (DOWN) PULSER COIL ELECTRIC BRACKET BATTERY PLATE GROUND 3 REC. /REG. ELECTRIC BRACKET CYLINDER BLOCK PLATE GROUND 1 DIODE MODULE #1 PT SWITCH DIODE MODULE #2...
  • Page 362 MFS8C/9.8C EP/EPT (RC12F) for US models Electric Circuit NEUTRAL SWITCH STARTER MOTOR STARTER MOTOR FUSE SOLENOID PT SOLENOID (UP) CYLINDER MAGNETO BLOCK CYLINDER BLOCK PT SOLENOID (DOWN) PULSER COIL ELECTRIC BRACKET BATTERY PLATE GROUND 3 REC. /REG. ELECTRIC BRACKET CYLINDER BLOCK PLATE GROUND 1 DIODE MODULE #1 PT SWITCH...
  • Page 363 Copyright © 2024 Tohatsu Corporation. All rights reserved. No part of this manual may be reproduced or transmitted in any form or by any means without the express written permission of Tohatsu Corporation.
  • Page 364 S E R V I C E M A N U A L STROKE MFS CZ MFS C MFS . C MFS . CY Models 5-4, Azusawa 3-Chome, Itabashi-Ku Tokyo 174-0051, Japan Tel: +81-3-3966-3117 Fax: +81-3-3966-2951 OB No.003-21079-0BD1 2404NB www.tohatsu.com Printed in Japan...

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