Advertisement

How to use this manual
A Few Words About Safety
How to use this manual
SERVICE INFORMATION
The service and repair information contained in this manual is intended for use by qualified, professional technicians. Attempting
service or repairs without the proper training, tools, and equipment could cause injury to you and/or others. It could also damage
this Honda product or create an unsafe condition.
This manual describes the proper methods and procedures for performing service, maintenance, and repairs. Some procedures
require the use of special tools. Any person who intends to use a replacement part, service procedure, or a tool that is not
recommended by Honda must determine the risks to his or her personal safety and the safe operation of this product.
If you need to replace a part, use Honda Genuine parts with the correct part number or an equivalent part. We strongly recommend
that you do not use replacement parts of inferior quality.
For Your Customer's Safety
Proper service and maintenance are essential to the customer's safety and the reliability of this product. Any error or oversight
while servicing this product can result in faulty operation, damage to the product, or injury to others.
Improper service or repairs can create an
unsafe condition that can cause your customer
or others to be seriously hurt or killed.
Follow the procedures and precautions in this
manual and other service materials carefully.
For Your Safety
Because this manual is intended for the professional service technician, we do not provide warnings about many basic shop safety
practices (Hot parts-wear gloves, for example). If you have not received shop safety training or do not feel confident about your
knowledge of safe servicing practice, we recommend that you do not attempt to perform the procedures described in this manual.
Some of the most important general service safety precautions are given below. However, we cannot warn you of every
conceivable hazard that can arise in performing service and repair procedures. Only you can decide whether or not you should
perform a given task.
Failure to properly follow instructions and
precautions can cause you to be seriously hurt
or killed.
Follow the procedures and precautions in this
manual carefully.
Important Safety Precautions
Make sure you have a clear understanding of all basic shop safety practices and that you are wearing appropriate clothing and
using safety equipment. When performing any service task, be especially careful of the following:
• Read all of the instructions before you begin, and make sure you have the tools, the replacement or repair parts, and the skills
required to perform the tasks safely and completely.
• Protect your eyes by using proper safety glasses, goggles, or face shields anytime you hammer, drill, grind, or work around
pressurized air, pressurized liquids, springs or other stored-energy components. If there is any doubt, put on eye protection.
• Use other protective wear when necessary, for example gloves or safety shoes. Handling hot or sharp parts can cause severe
burns or cuts. Before you grab something that looks like it can hurt you, stop and put on gloves.
• Protect yourself and others whenever you have engine-power equipment up in the air. Anytime you lift this product with a hoist,
make sure that the hoist hook is securely attached to the product.
Make sure the engine is off before you begin any servicing procedures, unless the instruction tells you to do otherwise. This will
help eliminate several potential hazards:
• Carbon monoxide poisoning from engine exhaust. Be sure there is adequate ventilation whenever you run the engine.
• Burns from hot parts. Let the engine and exhaust system cool before working in those areas.
• Injury from moving parts. If the instruction tells you to run the engine, be sure your hands, fingers and clothing are out of the way.
Gasoline vapors and hydrogen gasses from battery are explosive. To reduce the possibility of a fire or explosion, be careful when
working around gasoline or batteries.
• Use only a nonflammable solvent, not gasoline, to clean parts.
• Never store gasoline in an open container.
• Keep all cigarettes, sparks, and flames away from the battery and all fuel-related parts.

Advertisement

Table of Contents
loading

Summary of Contents for Honda WT30XK4

  • Page 1 Honda must determine the risks to his or her personal safety and the safe operation of this product. If you need to replace a part, use Honda Genuine parts with the correct part number or an equivalent part. We strongly recommend that you do not use replacement parts of inferior quality.
  • Page 2: Table Of Contents

    CONTENTS SPECIFICATIONS SERVICE INFORMATION MAINTENANCE TROUBLESHOOTING COVER FUEL SYSTEM GOVERNOR SYSTEM IGNITION SYSTEM STARTING SYSTEM PUMP ENGINE REMOVAL/INSTALLATION CYLINDER HEAD/VALVES CRANKCASE MUFFLER WIRING DIAGRAM INDEX...
  • Page 3 ALL INFORMATION, ILLUSTRATIONS, DIRECTIONS AND SPECIFICATIONS INCLUDED IN THIS PUBLICATION ARE BASED ON THE LATEST PRODUCT INFORMATION AVAILABLE AT THE TIME OF APPROVAL FOR PRINTING. Honda Motor Co., Ltd. RESERVES THE RIGHT TO MAKE CHANGES AT ANY TIME WITHOUT NOTICE AND WITHOUT INCURRING ANY OBLIGATION WHATSOEVER.
  • Page 4 How to use this manual SERVICE RULES • Use Honda Genuine or Honda-recommended parts and lubricants or their equivalents. Parts that do not meet Honda’s design specifications may damage the unit. • Use the special tools designed for the product.
  • Page 5 How to use this manual ABBREVIATIONS Throughout this manual, the following abbreviations are used to identify the respective parts or systems. Abbreviated Full term term Alternator American Petroleum Institute Approx. Approximately Assy. Assembly ATDC After Top Dead Center Automatic Transmission Fluid Attachment Auto Voltage Regulator Battery...
  • Page 6: Specifications

    dummytext 1. SPECIFICATIONS SERIAL NUMBER LOCATION ·····················1-2 PERFORMANCE CURVES··························· 1-4 SPECIFICATIONS ·········································1-2 DIMENSIONAL DRAWINGS························· 1-5...
  • Page 7 The frame serial number is located on the frame. Refer to these numbers when ordering parts and when making technical inquiries. ENGINE SERIAL NUMBER FRAME SERIAL NUMBER SPECIFICATIONS DIMENSIONS AND WEIGHTS Model WT30XK4 WT40XK3 Description code WAWJ WAYJ Type AC, C Overall length 660 mm (26.0 in)
  • Page 8 SPECIFICATIONS ENGINE Model WT30XK4 WT40XK3 Engine model GX270T2 GX390T2 Description code GCBHT GCBDT Type 4 stroke, overhead valve, single cylinder, inclined by 25° Displacement 270 cm (16.5 cu–in) 389 cm (23.7 cu–in) Bore x stroke 77.0 x 58.0 mm (3.03 x 2.28 in) 88.0 x 64.0 mm (3.46 x 2.52 in)
  • Page 9 SPECIFICATIONS PERFORMANCE CURVES WT30XK4 meters(feet) 30.5 (100) 24.4 (80) 18.3 (60) 12.2 (40) 6.1 (20) (50) (100) (150) (200) (250) (300) (350) (400) (gallons) 1136 1324 1514 liters WT40XK3 meters(feet) 30.5 (100) 24.4 (80) 18.3 (60) 12.2 (40) 6.1 (20)
  • Page 10 SPECIFICATIONS DIMENSIONAL DRAWINGS Unit: mm (in) 660 (26.0) (WT30XK4) 735 (28.9) (WT40XK3) 495 (19.5) (WT30XK4) 535 (21.1) (WT40XK3)
  • Page 11 MEMO...
  • Page 12: Service Information

    dummytext 2. SERVICE INFORMATION MAINTENANCE STANDARDS ·····················2-2 TOOLS ·························································· 2-6 TORQUE VALUES ········································2-4 HARNESS AND TUBE ROUTING ················ 2-9 LUBRICATION & SEAL POINTS··················2-5...
  • Page 13 SERVICE INFORMATION MAINTENANCE STANDARDS SERVICE INFORMATION WT30XK4 Unit: mm (in) Part Item Standard Service limit Engine Maximum speed (at no load) – 3,850 ± 150 min (rpm) Idle speed – 1,400 ± 150 min (rpm) 0.50 -0.70 MPa (5.1- 7.1 kgf/cm Cylinder compression –...
  • Page 14 SERVICE INFORMATION WT40XK3 Unit: mm (in) Part Item Standard Service limit Engine Maximum speed (at no load) – 3,850 ± 150 min (rpm) Idle speed – 1,400 ± 150 min (rpm) 0.51 - 0.69 MPa (5.2 - 7.0 kgf/cm Cylinder compression –...
  • Page 15 Rocker arm pivot lock nut M6 x 0.5 Spark plug M14 x 1.25 (Special) Oil level switch joint nut M10 x 1.25 Flywheel nut (WT30XK4 / GX270T2) M16 x 1.5 (Special nut) 13.1 Flywheel nut (WT40XK3 / GX390T2) M16 x 1.5 (Special nut) 17.3 Fuel tank nut/bolt M8 x 1.25...
  • Page 16 SERVICE INFORMATION LUBRICATION & SEAL POINTS ENGINE Location Material Remarks Crankshaft pin and gear teeth Engine oil Piston outer surface and piston ring Piston pin outer surface Cylinder barrel inner surface Connecting rod big and small end bearing Connecting rod bolt threads and seating surface Camshaft cam journal and lobes Valve lifter pivot, pivot end and slipper surface Valve stem sliding surface and stem end...
  • Page 17 SERVICE INFORMATION TOOLS SPECIAL TOOLS Special tools used in this manual can be ordered using normal American Honda parts ordering procedures. Float level gauge Remover weight Attachment, 32 x 35 mm 07401-0010000 07936-371020A 07746-0010100 Attachment, 52 x 55 mm Attachment, 72 x 75 mm Driver, 40 mm I.D.
  • Page 18 SERVICE INFORMATION Driver Bearing remover shaft, 15 Bearing remover head, 15 07749-0010000 07936-KC10100 07936-KC10200 Valve guide driver, 6.0 × 11.5 mm Attachment, 45 x 50 mm Attachment, 62 x 64 mm 07942-6570100 07946-6920100 07947-6340400 Valve guide reamer, 6.612 mm Puller collar set Vacuum tester 07984-ZE2000D 07APC-ZY1A100...
  • Page 19 SERVICE INFORMATION COMMERCIALLY AVAILABLE TOOLS Tool name Tool number Application Digital multimeter FLU88 Electrical testing Valve seat cutter, 30 x 45 degree NWYCU128 Valve seat reconditioning Valve seat cutter, 60 degree NWYCU114 Solid pilot bar, 6.6 mm NWY100-6.60 T handle NWYTW505 Strap wrench S-17...
  • Page 20 SERVICE INFORMATION HARNESS AND TUBE ROUTING ENGINE STOP SWITCH ENGINE WIRE HARNESS HARNESS CLIP OIL LEVEL SWITCH OIL LEVEL SWITCH ENGINE STOP CORD SWITCH CONNECTOR To engine To ignition coil stop switch HARNESS CLIP INSIDE YELLOW BLACK YELLOW BLACK ENGINE STOP SWITCH CORD To oil level switch ENGINE STOP...
  • Page 21 SERVICE INFORMATION ENGINE WIRE GOVERNOR ARM HARNESS HIGH-TENSION CONTROL BASE CORD CONTROL BASE CYLINDER BARREL RIB CARBURETOR INSULATOR IGNITION COIL HIGH-TENSION BREATHER TUBE CORD TUBE CLAMP (2) TUBE CLIP YELLOW MARK 2 - 4 mm (0.1 - 0.2 in) 2 - 4 mm (0.1 - 0.2 in) FUEL TUBE 2-10...
  • Page 22: Maintenance

    dummytext 3. MAINTENANCE MAINTENANCE SCHEDULE························3-2 VALVE CLEARANCE CHECK/ADJUSTMENT ································ 3-9 ENGINE OIL LEVEL CHECK/CHANGE ·······3-3 COMBUSTION CHAMBER CLEANING ····· 3-11 AIR CLEANER CHECK/CLEANING/REPLACEMENT ··········3-5 FUEL TANK AND FILTER CLEANING ······ 3-11 SEDIMENT CUP CLEANING ························3-6 FUEL TUBE CHECK ··································· 3-12 SPARK PLUG IMPELLER CHECK ·····································...
  • Page 23: Maintenance Schedule

    MAINTENANCE MAINTENANCE SCHEDULE MAINTENANCE REGULAR SERVICE PERIOD (2) Perform at every indicated month or operating hour interval, whichever comes first. Refer to Item First Every Every Every page Each use After use month or 3 months or 6 months or year or 20 hrs.
  • Page 24: Engine Oil Level Check/Change

    MAINTENANCE ENGINE OIL LEVEL CHECK/CHANGE LEVEL CHECK Place the water pump on a level surface. Remove the oil filler cap (1), and wipe the oil level gauge (2) clean. Insert the oil filler cap without screwing it into the oil filler neck (3).
  • Page 25 MAINTENANCE CHANGE Drain the oil in the engine while the engine is warm. Warm oil drains quickly and completely. The pump housing must be filled with water when the engine is started to warm up the oil. Place the water pump on a level surface, and place a suitable container under the drain plug bolt.
  • Page 26: Air Cleaner

    MAINTENANCE AIR CLEANER CHECK/CLEANING/ REPLACEMENT CHECK/REPLACEMENT A dirty air filter will restrict air flow to the carburetor, reducing engine performance. If the engine is operated in dusty areas, clean the air cleaner more often than specified in the MAINTENANCE SCHEDULE. Operating the engine without the air filters or with the filter installed loosely will allow dirt to enter the engine, causing rapid engine wear.
  • Page 27: Sediment Cup Cleaning

    MAINTENANCE INNER FILTER (PAPER) Tap the inner filter (1) lightly several times on a hard surface to remove excess dirt, or blow compressed air lightly (207 kPa (2.11 kgf/cm , 30 psi) or less) through the paper filter from inside. Never try to brush the dirt off;...
  • Page 28 MAINTENANCE SPARK PLUG CHECK/ADJUSTMENT/ REPLACEMENT CHECK/ADJUSTMENT If the engine has been running, the engine will be very hot. Allow it to cool before proceeding. Remove the spark plug cap, and then remove the spark plug (1) using a spark plug wrench (2). Visually check the spark plug.
  • Page 29: Spark Plug

    Allow it to cool before proceeding. Remove the 5 x 8 mm tapping screws (1), R. muffler WT30XK4: protector (2), and L. muffler protector (3). WT30XK4: Remove the 4 x 6 mm tapping screw (4) and spark arrester (5).
  • Page 30: Idle Speed Check/Adjustment

    MAINTENANCE Be careful to avoid damaging the screen. Clean the carbon deposits from the spark arrester screen (1) with a wire brush (2). Check the spark arrester screen for damage. If the screen is damaged, replace the spark arrester. Install the spark arrester in the reverse order of removal.
  • Page 31: Valve Clearance

    MAINTENANCE Disconnect the spark plug cap from the spark plug. Set the piston near top dead center of the cylinder compression stroke (both valves fully closed) by pulling the recoil starter slowly. When the piston is near top dead center of the compression stroke, the triangle Pull slowly.
  • Page 32: Combustion Chamber Cleaning

    MAINTENANCE COMBUSTION CHAMBER CLEANING Remove the cylinder head (page 12-3). Clean any carbon deposits from the combustion chamber (1). Installation is in the reverse order of removal. FUEL TANK AND FILTER CLEANING Gasoline is highly flammable and explosive. You can be burned or seriously injured when handling fuel.
  • Page 33: Fuel Tube Check

    MAINTENANCE FUEL TUBE CHECK Gasoline is highly flammable and explosive. You can be burned or seriously injured when handling fuel. • Keep heat, sparks, and flame away. • Handle fuel only outdoors. • Wipe up spills immediately. Check the fuel tube (1) for deterioration, cracks, or signs of leakage.
  • Page 34: Impeller Clearance Check

    Measure the clearance between the impeller (1) and volute case (2) using a feeler gauge (3). IMPELLER CLEARANCE: WT30XK4: 0.4 - 0.8 mm (0.016 - 0.031 in) WT40XK3: 0.5 - 0.8 mm (0.020 - 0.031 in) If not, adjust clearance by adding or removing adjuster shims (page 10-4).
  • Page 35 MEMO...
  • Page 36: Troubleshooting

    dummytext 4. TROUBLESHOOTING BEFORE TROUBLESHOOTING···················4-2 WATER PUMP TROUBLESHOOTING········· 4-6 ENGINE TROUBLESHOOTING····················4-2...
  • Page 37 TROUBLESHOOTING BEFORE TROUBLESHOOTING TROUBLESHOOTING • Check that the connectors are connected securely. • Check for sufficient fresh fuel in the fuel tank. • Read the circuit tester's operation instructions carefully, and observe the instructions during inspection. ENGINE TROUBLESHOOTING ENGINE LOCKED UP Remove the front cover and volute case (page Remove any foreign materials.
  • Page 38 TROUBLESHOOTING ENGINE WON’T START • Check the oil level before troubleshooting (page 3-3). Loosen the carburetor drain screw and check the Check for clogged fuel tank joint or fuel tube No fuel fuel flow from the fuel tank (page 6-3, 6-6). (page 6-3, 6-6).
  • Page 39 TROUBLESHOOTING ENGINE SURGES Be sure the pump housing is filled with water when the engine is started or mechanical seal damage will occur. Allow engine to reach normal operating Normal operation. RPM stabilizes temperature. Does not stabilize Inspect governor linkage and carburetor throttle Partially apply the choke lever.
  • Page 40 TROUBLESHOOTING ENGINE DOES NOT STOP WHEN ENGINE STOP SWITCH IS TURNED OFF Check the engine stop switch (page 8-9). Replace the engine stop switch (page 5-2). Abnormal Normal Check the wire harness connecting the engine Replace or repair the engine wire harness. No continuity stop switch and the ignition coil for open or short circuit.
  • Page 41 TROUBLESHOOTING WATER PUMP TROUBLESHOOTING PUMP WON’T PRIME Perform vacuum test (page 10-7). Check customer's system and usage. Vacuum normal • Customer not filling pump housing with water prior to starting. • Air leak in suction hose and / or fitting. Low vacuum •...
  • Page 42: Cover

    dummytext 5. COVER FAN COVER REMOVAL/INSTALLATION····5-2...
  • Page 43 COVER FAN COVER REMOVAL/INSTALLATION COVER Open the harness clip and disconnect the engine stop switch connector. When installing, refer to the HARNESS ROUTING (page 2-9). TAPPING SCREW (3 x 6 mm) (2) HARNESS CLIP 0.45 N·m (0.046 kgf·m, 0.33 lbf·ft) TUBE CLIP FAN COVER REMOVAL:...
  • Page 44: Fuel System

    dummytext 6. FUEL SYSTEM TOOLS···························································6-2 CARBURETOR BODY CLEANING ·············· 6-8 FUEL TANK REMOVAL/INSTALLATION ····6-3 CARBURETOR INSPECTION ······················ 6-8 AIR CLEANER PILOT SCREW REPLACEMENT ················· 6-9 REMOVAL/INSTALLATION··························6-5 CHOKE SET REPLACEMENT ··················· 6-10 CARBURETOR REMOVAL/INSTALLATION··························6-6 CYLINDER STUD BOLT REPLACEMENT ········································· 6-10 CARBURETOR DISASSEMBLY/ASSEMBLY ························6-7...
  • Page 45 FUEL SYSTEM TOOLS FUEL SYSTEM Float level gauge Jet cleaner set 07401-0010000 07JPZ-001010B...
  • Page 46 FUEL SYSTEM FUEL TANK REMOVAL/INSTALLATION Gasoline is highly flammable and explosive. You can be burned or seriously injured when handling fuel. • Keep heat, sparks, and flame away. • Handle fuel only outdoors. • Wipe up spills immediately. Drain the fuel into a suitable container. FUEL FILLER CAP PACKING FUEL FILLER CAP (AC type)
  • Page 47 FUEL SYSTEM FUEL FILTER HOLDER REMOVAL/INSTALLATION (AC TYPE ONLY) Remove the fuel filler cap (1). Turn the fuel filter holder (2) to align it the tether hole (3) with the cutout (4) of the fuel filler neck, and then remove the fuel filler cap. Before installing, check the air vent hole of the fuel filler cap for clogs.
  • Page 48 FUEL SYSTEM AIR CLEANER REMOVAL/INSTALLATION BREATHER TUBE INSTALLATION: After installing the air cleaner elbow, insert the breather tube into the hole AIR CLEANER of the cylinder head cover as shown. COVER WING NUT HIGH TENSION CORD BREATHER TUBE AIR CLEANER ELEMENT (PAPER) GROMMET ANGLED END...
  • Page 49 FUEL SYSTEM CARBURETOR REMOVAL/INSTALLATION Gasoline is highly flammable and explosive. You can be burned or seriously injured when handling fuel. • Keep heat, sparks, and flame away. • Handle fuel only outdoors. • Wipe up spills immediately. Turn the fuel valve lever to the OFF position. Remove the air cleaner (page 6-5).
  • Page 50 FUEL SYSTEM CARBURETOR DISASSEMBLY/ASSEMBLY Gasoline is highly flammable and explosive. You can be burned or seriously injured when handling fuel. • Keep heat, sparks, and flame away. • Handle fuel only outdoors. • Wipe up spills immediately. To prevent serious eye injury, always wear safety goggles or other eye protection when using compressed air.
  • Page 51 Check container instructions. If you are in doubt, do not use these products to clean Honda carburetors. • High air pressure may damage the carburetor body. Use low air pressure (30 psi or less) when cleaning passages and ports.
  • Page 52 Turn the pilot screw in until it is lightly seated, and then STOP turn the screw out the required number of turns. PILOT SCREW OPENING: WT30XK4: 2 turns out WT40XK3: 2 - 1/8 turns out Refer to the table above for carburetor pilot screw initial opening setting.
  • Page 53 REPLACEMENT Thread two nuts onto the stud bolt and tighten them together, and then use a wrench to turn the stud bolt out. WT30XK4: Install new stud bolts. STUD BOLT (8 x 123.0): 107.0 mm (4.21 in) SPECIFIED LENGTH WT40XK3: WT30XK4: STUD BOLT (8 x 131.5): 115.5 mm (4.55 in)
  • Page 54: Governor System

    dummytext 7. GOVERNOR SYSTEM GOVERNOR ARM/CONTROL BASE CONTROL BASE REMOVAL/INSTALLATION··························7-2 DISASSEMBLY/ASSEMBLY ························ 7-3 MAXIMUM SPEED ADJUSTMENT ·············· 7-4...
  • Page 55 GOVERNOR SYSTEM GOVERNOR ARM/CONTROL BASE GOVERNOR SYSTEM REMOVAL/INSTALLATION Remove the following parts. – Air cleaner (page 6-5) – Muffler (page 14-2) – Fuel tank (page 6-3) After installation, adjust the maximum speed (page 7-4). CONTROL BASE BOLT (6 x 12 mm) (2) GOVERNOR ROD/THROTTLE GOVERNOR SPRING RETURN SPRING...
  • Page 56 GOVERNOR SYSTEM CONTROL BASE DISASSEMBLY/ASSEMBLY Remove the control base (page 7-2). NUT (6 mm) CONTROL LEVER WASHER ASSEMBLY: ASSEMBLY: Install the control lever washer After tightening the nut fully, by aligning the cutout of the loosen it 1–1/2 turns. control lever washer with the tab of the control base.
  • Page 57 GOVERNOR SYSTEM MAXIMUM SPEED ADJUSTMENT Remove the fuel tank (page 6-3). Loosen the 6 mm nut (1) of the governor arm. Turn the governor arm (2) counterclockwise to fully open the carburetor throttle valve (3). Rotate the governor arm shaft (4) as far as it will go in the same direction the governor arm moved to open the throttle valve.
  • Page 58: Ignition System

    dummytext 8. IGNITION SYSTEM TOOL ·····························································8-2 SPARK TEST ················································ 8-7 SYSTEM DIAGRAM ······································8-3 SPARK PLUG CAP INSPECTION················ 8-7 IGNITION SYSTEM IGNITION COIL INSPECTION ······················ 8-8 TROUBLESHOOTING···································8-3 OIL LEVEL SWITCH INSPECTION ·············· 8-9 COOLING FAN/FLYWHEEL REMOVAL/INSTALLATION··························8-4 ENGINE STOP SWITCH INSPECTION ········ 8-9 IGNITION COIL REMOVAL/INSTALLATION··························8-6...
  • Page 59 IGNITION SYSTEM TOOL IGNITION SYSTEM Puller collar set 07APC-ZY1A100...
  • Page 60 IGNITION SYSTEM SYSTEM DIAGRAM ENGINE STOP SWITCH EXT ( + ) EXT ( - ) Black Brown Yellow Orange ENGINE STOP Blue Light blue SWITCH Green Light green Pink OIL LEVEL SPARK IGNITION White Gray SWITCH PLUG COIL IGNITION SYSTEM TROUBLESHOOTING NO SPARK AT SPARK PLUG •...
  • Page 61 IGNITION SYSTEM COOLING FAN/FLYWHEEL REMOVAL/INSTALLATION REMOVAL Remove the following parts: – Fan cover (page 5-2). – Ignition coil (page 8-6). WOODRUFF KEY (25 x 18 mm) STARTER PULLEY COOLING FAN FLYWHEEL NUT (16 mm) REMOVAL: REMOVAL: Hold the flywheel with a commercially available Hold the flywheel with a commercially available strap strap wrench and remove the 16 mm nut.
  • Page 62 Hold the flywheel (2) with a commercially available seating surface) strap wrench (S-17) (3), and tighten the 16 mm nut to the specified torque. TORQUE: WT30XK4: 128 N·m (13.1 kgf·m,94 lbf·ft) WT40XK3: 170 N·m (17.3 kgf·m,125 lbf·ft) Install the following parts: –...
  • Page 63 IGNITION SYSTEM IGNITION COIL REMOVAL/INSTALLATION REMOVAL Remove the following parts: – Air cleaner (page 6-5) – Fuel tank (page 6-3) – Fan cover (page 5-2) ENGINE WIRE HARNESS INSTALLATION: Clamp the engine wire harness to the ribs of the cylinder barrel as shown. ENGINE WIRE HARNESS Viewed from above SPARK PLUG CAP...
  • Page 64 IGNITION SYSTEM INSTALLATION Attach the ignition coil (1) and loosely tighten the two 6 0.2 – 0.6 mm x 28 mm bolts (2). (0.01 – 0.02 in) Insert the thickness gauge (3) of proper thickness between the ignition coil and the flywheel. IGNITION COIL AIR GAP: 0.2 –...
  • Page 65 IGNITION SYSTEM IGNITION COIL INSPECTION Disconnect the spark plug cap from the spark plug. Remove the spark plug cap from the high tension cord (1). Disconnect the ignition coil 4P connector (2) of the engine wire harness from the ignition coil. Measure the resistance between the terminals and be sure that...
  • Page 66 IGNITION SYSTEM OIL LEVEL SWITCH INSPECTION Disconnect the engine wire harness from the oil level switch. Check continuity between the switch terminal and engine ground. There should be no continuity when the engine is full of oil. Drain the engine oil completely (page 3-4). Check continuity between the switch terminal and engine ground.
  • Page 67 MEMO...
  • Page 68: Starting System

    dummytext 9. STARTING SYSTEM RECOIL STARTER RECOIL STARTER REMOVAL/INSTALLATION··························9-2 DISASSEMBLY/ASSEMBLY ························ 9-3 RECOIL STARTER INSPECTION ················ 9-6...
  • Page 69 STARTING SYSTEM RECOIL STARTER STARTING SYSTEM REMOVAL/INSTALLATION RECOIL STARTER BOLT (6 x 10 mm)
  • Page 70 STARTING SYSTEM RECOIL STARTER DISASSEMBLY/ASSEMBLY DISASSEMBLY • Wear gloves and eye protection. • During disassembly/assembly, take care not to allow the return spring to come out. Remove the recoil starter (page 9-2). CENTER SCREW 3.9 N·m (0.4 kgf·m, 35 lbf·in) SPRING RETAINER FRICTION SPRING RATCHET (2)
  • Page 71 STARTING SYSTEM ASSEMBLY • Wear gloves and eye protection. • During disassembly/assembly, take care not to allow the return spring to come out. Pass the recoil starter rope (1) through the hole (2) of the recoil starter pulley (3), and then tie the rope as shown.
  • Page 72 STARTING SYSTEM Apply grease to the two ratchets (1). Install the two ratchets and the two ratchet springs (2) to the recoil starter pulley as shown. Apply grease to the inside of the spring retainer (1). Set the friction spring (2) and the spring retainer to the recoil starter pulley in the direction as shown.
  • Page 73 STARTING SYSTEM RECOIL STARTER INSPECTION RECOIL STARTER OPERATION Remove the recoil starter (page 9-2). Pull the starter grip several times to inspect that the ratchets (1) are operated properly (the ratchet ends come out from the spring retainer (2)). STARTER PULLEY Remove the recoil starter (page 9-2).
  • Page 74: Pump

    dummytext 10. PUMP TOOL ···························································10-2 FRONT COVER DISASSEMBLY/ASSEMBLY ······················ 10-5 FRONT COVER REMOVAL/INSTALLATION························10-3 CASING DISASSEMBLY/ASSEMBLY ······· 10-6 CASING REMOVAL/INSTALLATION·········10-4 PUMP VACUUM TEST ······························· 10-7 10-1...
  • Page 75: Tool

    PUMP TOOL PUMP Vacuum gauge 07APJ-YB3A100 10-2...
  • Page 76: Front Cover Removal/Installation

    PUMP FRONT COVER REMOVAL/INSTALLATION Loosen the wing bolt and remove the tool (page 10-4). Loosen the front cover knob, using the tool. HOSE COUPLING PACKING FRONT COVER (Commercially available) CHECK: Replace if necessary. HOSE CLAMP RING (Commercially available) FRONT COVER KNOB (4) 43 N·m (4.3 kgf·m, 30 lbf·ft) HOSE COUPLING (Commercially available)
  • Page 77: Casing Removal/Installation

    WT40XK3: WASHER (8 mm) (4) HOSE BAND HOSE CLAMP RING BOLT (Commercially available) WT30XK4: (8 x 55 mm) (4) 20 N·m (2.0 kgf·m, 14 lbf·ft) WT40XK3: (8 x 50 mm) (4) 22 N·m (2.2 kgf·m, 16 lbf·ft) IMPELLER REMOVAL: Remove the impeller (1) by giving it a shock using a wooden stick (2) and hammer as shown, taking care not to damage the impeller.
  • Page 78: Front Cover

    O-RING VOLUTE CASE CHECK: Replace if necessary. WASHER (8 mm) (3) BOLT WT30XK4: (10 x 25 mm) (6) 7 N·m (0.7 kgf·m, 5.2 lbf·ft) WT40XK3: (12 x 35 mm) (6) INLET 10 N·m (1.0 kgf·m, 7 lbf·ft) INLET VALVE FRONT COVER ASSEMBLY: Install the inlet valve as shown.
  • Page 79: Casing Disassembly/Assembly

    O-RING (25 mm) CHECK: Replace if necessary. CASING BOLT PLUG (25 mm) WT30XK4: (10 x 30 mm) (4) 7 N·m (0.7 kgf·m, 5.2 lbf·ft) WT40XK3: (12 x 35 mm) (4) 10 N·m (1.0 kgf·m, 7 lbf·ft) BOLT FRONT COVER BOLT (4)
  • Page 80: Pump Vacuum Test

    PUMP PUMP VACUUM TEST TEST Fill the pump housing with water. Position garden hose (1) in the discharge port turn the hose on so a steady stream of water flows out the port. This will ensure the pump housing remains completely full during the test.
  • Page 81 MEMO...
  • Page 82: Engine Removal/Installation

    dummytext 11. ENGINE REMOVAL/INSTALLATION ENGINE REMOVAL/INSTALLATION ·········11-2 11-1...
  • Page 83 ENGINE REMOVAL/INSTALLATION ENGINE REMOVAL/INSTALLATION ENGINE REMOVAL/INSTALLATION Remove the casing (page 10-4). BOLT WT30XK4: (10 x 35 mm) (2) WT40XK3: (10 x 40 mm) (2) 25 N·m (2.5 kgf·m, 18 lbf·ft) FRAME NUT (10 mm) (2) BOTTOM RUBBER (2) INSTALLATION: NUT (8 mm) (2)
  • Page 84: Cylinder Head/Valves

    dummytext 12. CYLINDER HEAD/VALVES TOOLS·························································12-2 CYLINDER HEAD/VALVES INSPECTION··············································· 12-5 CYLINDER HEAD REMOVAL/INSTALLATION························12-3 VALVE GUIDE REPLACEMENT ················ 12-8 CYLINDER HEAD VALVE GUIDE REAMING ·························· 12-9 DISASSEMBLY/ASSEMBLY ······················12-4 VALVE SEAT RECONDITIONING············ 12-10 12-1...
  • Page 85 CYLINDER HEAD/VALVES TOOLS CYLINDER HEAD/VALVES Valve guide driver, 6.0 × 11.5 mm Valve guide reamer, 6.612 mm 07942-6570100 07984-ZE2000D 12-2...
  • Page 86 CYLINDER HEAD/VALVES CYLINDER HEAD REMOVAL/INSTALLATION Set the piston at top dead center of the cylinder compression stroke (page 3-9). Remove the following parts: – Carburetor (page 6-6) – Control base (page 7-2) – Muffler (page 14-2) After installation, check the valve clearance, and if necessary, adjust the clearance (page 3-9).
  • Page 87 CYLINDER HEAD/VALVES CYLINDER HEAD DISASSEMBLY/ASSEMBLY Remove the cylinder head (page 12-3). INTAKE/EXHAUST VALVE SPRING RETAINER CYLINDER HEAD DISASSEMBLY: Push down and slide the valve spring retainer (1) to the side so that the SPARK PLUG valve stem slips through the hole at 18 N·m (1.8 kgf·m, 13 lbf·ft) the side of the valve spring retainer.
  • Page 88 EEPV303A (2) to the spark plug hole. Pull the recoil starter forcefully to measure stable cylinder compression. CYLINDER COMPRESSION: WT30XK4: 0.50 - 0.70 MPa (5.1 - 7.1 kgf/cm 73 - 101 psi) / 600 min (rpm) WT40XK3: 0.51 - 0.69 MPa (5.2 - 7.0 kgf/cm...
  • Page 89 CYLINDER HEAD/VALVES If the valve seat is too high or too low, recondition the valve seat (page 12-10). VALVE GUIDE I.D. Ream the valve guide (1) to remove any carbon T-HANDLE deposits before measuring. NWYT505 (Commercially available) TOOL: Valve guide reamer, 6.612 mm (2) 07984-ZE2000D Turn the special tool (Valve guide reamer) clockwise, never counterclockwise.
  • Page 90 CYLINDER HEAD/VALVES VALVE STEM O.D. Inspect each valve for bending or abnormal stem wear. If necessary, replace the valve (page 12-4). Measure and record each valve stem O.D. STANDARD: IN: 6.575 – 6.590 mm (0.2589 – 0.2594 in) EX: 6.535 – 6.550 mm (0.2573 – 0.2579 in) SERVICE LIMIT: IN: 6.44 mm (0.254 in) EX: 6.40 mm (0.252 in)
  • Page 91 CYLINDER HEAD/VALVES VALVE SPRING PERPENDICULARITY Measure the valve spring perpendicularity. SERVICE LIMIT: 1.5° If the measured perpendicularity is more than the service limit, replace the valve spring (page 12-4). PUSH ROD RUNOUT Check both ends of the push rod for wear. Check the push rod for straightness.
  • Page 92 Intake valve guide (4): Drive the intake valve guide to the specified height (measured from the end of the valve guide to the cylinder head as shown). WT30XK4: 6 mm (0.24 in) WT40XK3: 5 mm (0.20 in) IN VALVE GUIDE INSTALLATION HEIGHT: WT30XK4: 6 mm (0.24 in)
  • Page 93 Replace the valve guide if it is bent or damaged. Check the valve guide-to-stem clearance (page 12-7). LVE SEAT RECONDITIONING Thoroughly clean the combustion chamber and valve VALVE LAPPER seats to remove carbon deposits. Remove the carbon LIL21100 from the valve seats by lightly lapping the valves with a (Commercially available) lapping compound.
  • Page 94 CYLINDER HEAD/VALVES The 32° cutter removes material from the top edge (contact too high). CONTACT TO STANDARD TOOLS: Solid pilot bar, 6.6 mm NWY100-6.60 Cutter, 30 x 45 degree NWYCU128 The 60° cutter removes material from the bottom edge (contact too low). VALVE FACE TOOLS: Solid pilot bar, 6.6 mm...
  • Page 95 MEMO...
  • Page 96: Crankcase

    dummytext 13. CRANKCASE TOOLS·························································13-2 CRANKCASE COVER/CYLINDER BARREL/ PISTON/CONNECTING ROD/CRANKSHAFT/ CAMSHAFT INSPECTION·························· 13-9 CRANKCASE COVER REMOVAL/INSTALLATION························13-4 CRANKSHAFT/BALANCER WEIGHT BEARING/OIL SEAL REPLACEMENT CRANKSHAFT/BALANCER/PISTON (CRANKCASE COVER SIDE) ·················· 13-16 REMOVAL/INSTALLATION························13-5 CRANKSHAFT BEARING REPLACEMENT BALANCER WEIGHT/CAMSHAFT (CRANKSHAFT SIDE) ······························ 13-19 INSTALLATION···········································13-6 CRANKSHAFT/BALANCER WEIGHT GOVERNOR BEARING/OIL SEAL REPLACEMENT DISASSEMBLY/ASSEMBLY ······················13-7 (CYLINDER BARREL SIDE)·····················...
  • Page 97 CRANKCASE TOOLS CRANKCASE Remover weight Attachment, 32 x 35 mm Attachment, 52 x 55 mm 07936-371020A 07746-0010100 07746-0010400 Attachment, 72 x 75 mm Driver, 40 mm I.D. Attachment, 30 mm I.D. 07746-0010600 07746-0030100 07746-0030300 Attachment, 35 mm I.D. Pilot, 15 mm Pilot, 30 mm 07746-0030400 07746-0040300...
  • Page 98 CRANKCASE Bearing remover shaft, 15 Bearing remover head, 15 Attachment, 45 x 50 mm 07936-KC10100 07936-KC10200 07946-6920100 Attachment, 62 x 64 mm 07947-6340400 13-3...
  • Page 99 CRANKCASE CRANKCASE COVER REMOVAL/INSTALLATION Drain the engine oil (page 3-4). Remove the casing (page 10-4). Position the engine at TDC of the compression stroke before removing the cover(page 3-9). CRANKCASE COVER OIL FILLER CAP DOWEL PIN (8 x 12 mm) (2) CASE COVER PACKING BOLT (8 x 40 mm) (7) 24 N·m (2.4 kgf·m, 18 lbf·ft)
  • Page 100 CRANKCASE CRANKSHAFT/BALANCER/PISTON REMOVAL/INSTALLATION Remove the following: – Engine (page 11-2) – Cylinder head (page 12-3) – Fuel tank (page 6-3) – Flywheel (page 8-4) – Crankcase cover (page 13-4) LOCK PIN (10 mm) PISTON INSTALLATION: INSTALLATION: Install the lock pin immediately after installing the Install the piston to the cylinder governor arm shaft in the direction as shown.
  • Page 101 CRANKCASE BALANCER WEIGHT/CAMSHAFT INSTALLATION BALANCER WEIGHT INSTALLATION (WT40XK3 ONLY) Install the balancer weight (1) to the cylinder barrel by aligning the punch marks (2) of the balancer weight and the crankshaft (3) (marked on the balancer drive gear (4)). CAMSHAFT INSTALLATION Install the camshaft (1) to the cylinder barrel by aligning the punch marks (2) of the camshaft and the crankshaft (3) (marked on the timing gear (4)).
  • Page 102 After installing the governor ASSEMBLY: slider, check to be sure it Install firmly into the groove. moves smoothly. GOVERNOR WEIGHT WT30XK4: (2) WT40XK3: (3) ASSEMBLY: GOVERNOR WEIGHT HOLDER After installing the governor weight, check to be sure they move smoothly.
  • Page 103 MARK OIL RING PISTON PISTON PIN PISTON PIN CLIP (2) WT30XK4: (18 mm) WT40XK3: (20 mm) ASSEMBLY: Install by setting one end of the piston pin clip in the groove of the piston pin bore, holding the other end with long needle pliers, and rotating the clip in.
  • Page 104 Measure and record the cylinder I.D. at three levels in both the “X” axis (perpendicular to crankshaft) and the “Y” axis (parallel to crankshaft). Take the maximum reading to determine cylinder wear and taper. WT30XK4: STANDARD: 77.000 – 77.017 mm (3.0315 – 3.0322 in)
  • Page 105 PISTON SKIRT O.D. Measure and record the piston O.D. at a point 10 mm (0.4 in) from the bottom of the skirt and 90 degrees to the piston pin bore. WT30XK4: 90° STANDARD: 76.975 – 76.985 mm (3.0305 – 3.0309 in) SERVICE LIMIT: 76.85 mm (3.026 in)
  • Page 106 CRANKCASE PISTON PIN O.D. Measure and record the piston pin O.D. at three points (both ends and middle). Take the minimum reading to determine piston pin O.D. WT30XK4: STANDARD: 17.994 – 18.000 mm (0.7084 – 0.7087 in) SERVICE LIMIT: 17.950 mm (0.7067 in)
  • Page 107 CRANKCASE PISTON RING WIDTH Measure each piston ring width. STANDARD: Top/second: 1.160 – 1.175 mm (0.0457 – 0.0463 in) SERVICE LIMIT: Top/second: 1.140 mm (0.0449 in) If any of the measurements is less than the service limit, replace the piston rings (top, second, oil) as a set (page 13-8).
  • Page 108 CRANKCASE CONNECTING ROD SMALL END I.D. Measure the connecting rod small end I.D. WT30XK4: STANDARD: 18.005 – 18.020 mm (0.7089 – 0.7094 in) SERVICE LIMIT: 18.07 mm (0.711 in) WT40XK3: STANDARD: 20.005 – 20.020 mm (0.7876 – 0.7882 in) SERVICE LIMIT: 20.07 mm (0.790 in)
  • Page 109 SERVICE LIMIT: 0.1 mm (0.004 in) If the measured runout is more than the service limit, replace the crankshaft (page 13-5). 16 mm WT30XK4: (0.6 in) 16 mm (0.6 in) WT40XK3 17 mm (0.7 in) 13-14...
  • Page 110 CRANKCASE CAMSHAFT CAM HEIGHT Measure the cam height of the camshaft. WT30XK4: STANDARD: IN: 31.895 – 32.195 mm (1.2557 – 1.2675 in) EX: 31.616 – 31.916 mm (1.2447 – 1.2565 in) SERVICE LIMIT: IN: 31.795 mm (1.2518 in) EX: 31.516 mm (1.2408 in)
  • Page 111 CRANKSHAFT/BALANCER WEIGHT BEARING/OIL SEAL REPLACEMENT (CRANKCASE COVER SIDE) LOCATION OUTSIDE: CRANKSHAFT OIL SEAL (WT30XK4: 30 x 45 x 8 mm) (WT40XK3: 35 x 52 x 8 mm) INSIDE: BALANCER WEIGHT BEARING (6202) CRANKSHAFT BEARING (WT40XK3 only) (WT30XK4: 6206)
  • Page 112 07746-0040800 Driver (4) 07749-0010000 CRANKSHAFT OIL SEAL (WT30XK4: 30 x 45 x 8 mm) (WT40XK3: 35 x 52 x 8 mm) Remove the oil seal from the crankcase cover. Apply grease to the lip of a new oil seal (1).
  • Page 113 CRANKCASE BALANCER WEIGHT BEARING (6202) (WT40XK3 ONLY) Pull out the radial ball bearing (1) using the special tools. TOOLS: Bearing remover head, 15 mm (2) 07936-KC10200 Bearing remover shaft, 15 mm (3) 07936-KC10100 Remover weight (4) 07936-371020A Apply oil to the circumference of a new bearing (5). Drive the radial ball bearing until it is fully seated on the end using the special tools.
  • Page 114 CRANKCASE CRANKSHAFT BEARING REPLACEMENT (CRANKSHAFT SIDE) CRANKSHAFT BEARING (WT30XK4: 6206) (WT40XK3: 6207) Install the 16 mm special nut (1) tightening the flywheel to protect the crankshaft threads. Pull out the radial ball bearing (2) using a commercially available bearing puller (3).
  • Page 115 (CYLINDER BARREL SIDE) LOCATION CRANKSHAFT OIL SEAL BALANCER WEIGHT BEARING (6202) (WT30XK4: 30 x 46 x 8 mm) (WT40XK3 only) (WT40XK3: 35 x 52 x 8 mm) GOVERNOR ARM SHAFT OIL SEAL (8 x 14 x 5 mm) CRANKSHAFT OIL SEAL...
  • Page 116 CRANKCASE BALANCER WEIGHT BEARING (6202) (WT40XK3 ONLY) Pull out the radial ball bearing (1) using the special tools. TOOLS: Bearing remover head, 15 mm (2) 07936-KC10200 Bearing remover shaft, 15 mm (3) 07936-KC10100 Remover weight (4) 07936-371020A Apply oil to the circumference of a new bearing (5). Drive the radial ball bearing until it is fully seated on the end using the special tools.
  • Page 117 MEMO...
  • Page 118: Muffler

    dummytext 14. MUFFLER MUFFLER REMOVAL/INSTALLATION······14-2 EXHAUST PIPE STUD BOLT REPLACEMENT ········································· 14-3 14-1...
  • Page 119 Be careful not to touch the muffler while it is hot. Allow it to cool before proceeding. WT30XK4 SPARK ARRESTER (OPTIONAL PART): SCREW (4 x 6 mm) SCREW (5 x 8 mm) (6) MUFFLER GASKET R.
  • Page 120 MUFFLER EXHAUST PIPE STUD BOLT REPLACEMENT Thread two nuts onto the exhaust pipe stud bolt (1) and tighten them together, then use a wrench to turn the stud bolt out. Install new stud bolts. SPECIFIED LENGTH: STUD BOLT (8 x 48): 32 mm (1.26 in) SHORT LONG 32 mm (1.26 in)
  • Page 121 MEMO...
  • Page 122: Wiring Diagram

    dummytext 15. WIRING DIAGRAM WIRING DIAGRAM······································15-2 15-1...
  • Page 123 WIRING DIAGRAM WIRING DIAGRAM WIRING DIAGRAM ENGINE STOP SWITCH EXT ( + ) EXT ( - ) Black Brown Yellow Orange ENGINE STOP Blue Light blue SWITCH Green Light green Pink OIL LEVEL SPARK IGNITION White Gray SWITCH PLUG COIL 15-2...
  • Page 124: Index

    INDEX dummytext INDEX AIR CLEANER CHECK/CLEANING/REPLACEMENT ···3-5 GOVERNOR DISASSEMBLY/ASSEMBLY ·················· 13-7 AIR CLEANER REMOVAL/INSTALLATION ···················6-5 HARNESS AND TUBE ROUTING·································· 2-9 BALANCER WEIGHT/CAMSHAFT INSTALLATION ····13-6 IDLE SPEED CHECK/ADJUSTMENT···························· 3-9 BEFORE TROUBLESHOOTING ····································4-2 IGNITION COIL INSPESTION········································ 8-8 CARBURETOR BODY CLEANING ································6-8 IGNITION COIL REMOVAL/INSTALLATION ················· 8-6 CARBURETOR DISASSEMBLY/ASSEMBLY ················6-7 IGNITION SYSTEM TROUBLESHOOTING···················...

This manual is also suitable for:

Wt40xk3

Table of Contents