Honda WB20XT2, WB30XT2 Manual

How to use this manual


A Few Words About Safety

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 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 their 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 (e.g., Hot parts-wear gloves). If you have not received shop safety training or do not feel confident about your knowledge of safe servicing practices, 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 equipment hoisted 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 batteries 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.

0-1

OUTLINE OF CHANGES

OUTLINE OF CHANGES

Item

Pump

(WB20XT3)

Before modification After modification

Pump

(WB30XT3)

0-5

CONTENTS

SPECIFICATIONS


MAINTENANCE

TROUBLESHOOTING

COVER

FUEL SYSTEM

GOVERNOR SYSTEM

IGNITION SYSTEM

STARTING SYSTEM

PUMP

ENGINE REMOVAL/INSTALLATION

CYLINDER HEAD

CRANKCASE

MUFFLER

WIRING DIAGRAM

INDEX

13

14

15

9

10

11

12

7

8

5

6

3

4

1

2


INTRODUCTION

This manual covers the service and repair procedures for Honda WB20XT2/WB30XT2 water pumps.

All information contained in this manual is based on the latest product information available at the time of printing. We reserve the right to make changes at anytime without notice.

No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form, by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission of the publisher. This includes text, figures, and tables.

As you read this manual, you will find information that is preceded by a prevent damage to this Honda product, other property, or the environment.

symbol. The purpose of this message is to help

SAFETY MESSAGES

Your safety, and the safety of others, are very important. To help you make informed decisions, we have provided safety messages and other safety information throughout this manual. Of course, it is not practical or possible to warn you about all the hazards associated with servicing these products. You must use your own good judgement.

You will find important safety information in a variety of forms, including:

• Safety Labels – on the product.

• Safety Messages – preceded by a safety alert symbol and one of three signal words, DANGER, WARNING, or CAUTION.

These signal words mean:

You WILL be KILLED or SERIOUSLY HURT if you don’t follow instructions.

You CAN be KILLED or SERIOUSLY HURT if you don’t follow instructions.

You CAN be HURT if you don’t follow instructions.

• Instructions – how to service these products correctly and safely.

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. NO PART OF THIS PUBLICATION MAY BE REPRODUCED WITHOUT

WRITTEN PERMISSION. THIS MANUAL IS WRITTEN FOR PERSONS WHO HAVE ACQUIRED BASIC KNOWLEDGE OF

MAINTENANCE ON Honda products.

© Honda Motor Co., Ltd.

SERVICE PUBLICATION OFFICE

Date of Issue: October 2011

0-3


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.

• Install new gaskets, O-rings, etc. when reassembling.

• When torquing bolts or nuts, begin with larger-diameter or inner bolts first and tighten to the specified torque diagonally, unless a particular sequence is specified.

• Clean parts in cleaning solvent upon disassembly. Lubricate any sliding surfaces before assembly.

• After assembly, check all parts for proper installation and operation.

• Many screws used in this machine are self-tapping. Be aware that cross-threading or overtightening these screws will strip the threads and ruin the hole.

Use only metric tools when servicing this unit. Metric bolts, nuts and screws are not interchangeable with non-metric fasteners. The use of incorrect tools and fasteners will damage the unit.

SYMBOLS

The symbols used throughout this manual show specific service procedures. If supplementary information is required pertaining to these symbols, it will be explained specifically in the text without the use of the symbols.

Replace the part(s) with new one(s) before assembly.

Use the recommend engine oil, unless otherwise specified.

Use molybdenum oil solution (mixture of the engine oil and molybdenum grease in a ratio of 1:1).

Use multi-purpose grease (lithium based multi-purpose grease NLGI #2 or equivalent).

Use marine grease (water resistant urea based grease).

Apply a locking agent. Use a medium strength locking agent unless otherwise specified.

Apply sealant.

x ( ) page 1-1

Use automatic transmission fluid.

Indicates the diameter, length, and quantity of metric bolts used.

Indicates the reference page.

0-4


ABBREVIATIONS

Throughout this manual, the following abbreviations are used to identify the respective parts or systems.

Abbreviated

ECM

EMT

EOP

EX

F

GND

HO2S

IAB

CKP

Comp.

CMP

CYL

DLC

D-AVR

EBT

ECT term

ACG

API

Approx.

Assy.

ATDC

ATF

ATT

AVR

BAT

BDC

BTDC

BARO

IAC

IAT

I.D.

IG or IGN

IN

INJ

L.

MAP

MIL

O.D.

OP

PGM-FI

P/N

Qty

R.

SAE

SCS

STD

SW

TDC

Full term

Alternator

American Petroleum Institute

Approximately

Assembly

After Top Dead Center

Automatic Transmission Fluid

Attachment

Auto Voltage Regulator

Battery

Bottom Dead Center

Before Top Dead Center

Barometric Pressure

Crankshaft Position

Complete

Camshaft Position

Cylinder

Data Link Connector

Digital Auto Voltage Regulator

Engine Block Temperature

Engine Coolant Temperature

Engine Control Module

Exhaust Manifold Temperature

Engine Oil Pressure

Exhaust

Front or Forward

Ground

Heated Oxygen sensor

Intake Air Bypass

Idle Air Control

Intake Air Temperature

Inside diameter

Ignition

Intake

Injection

Left

Manifold Absolute Pressure

Malfunction Indicator Lamp

Outside Diameter

Optional Part

Programmed-Fuel Injection

Part Number

Quantity

Right

Society of Automotive Engineers

Service Check Signal

Standard

Switch

Top Dead Center

BI

Y

Black

Yellow

BU Blue

G

R

W

Green

Red

White

Br

O

Lb

Brown

Orange

Lg

P

Light blue Gr

Light green

Pink

Gray

0-5

dummytext

1. SPECIFICATIONS

1

SERIAL NUMBER LOCATION ·····················1-2

SPECIFICATIONS ·········································1-2

PERFORMANCE CURVES··························· 1-4

DIMENSIONAL DRAWINGS························· 1-5

1-1

SPECIFICATIONS

SPECIFICATIONS

SERIAL NUMBER LOCATION

The engine serial number is located on the cylinder barrel.

The frame serial number is located on the engine bed.

Refer to these numbers when ordering parts and when making technical inquiries.

WB20XT2•WB30XT2

ENGINE SERIAL NUMBER

SPECIFICATIONS

DIMENSIONS AND WEIGHTS

Model

Description code

Type

Overall length

Overall width

Overall height

Dry weight

Operating weight

WB20XT2

WABT

A, C

455 mm (17.9 in)

365 mm (14.4 in)

420 mm (16.5 in)

21 kg (46 lbs)

23 kg (51 lbs)

FRAME SERIAL NUMBER

WB30XT2

WACT

A, C

510 mm (20.1 in)

385 mm (15.2 in)

455 mm (17.9 in)

27 kg (60 lbs)

29 kg (64 lbs)

1-2


ENGINE

Model

Engine model

Description code

Type

Displacement

Bore x stroke

Compression ratio

Ignition system

Ignition timing

Spark plug

Lubrication system

Oil capacity

Recommended oil

Cooling system

Starting system

Stopping system

Carburetor

Air cleaner

Governor

Breather system

Fuel tank capacity

Fuel used

WATER PUMP

Model

Type

Drive system

Suction port diameter

Discharge port diameter

Maximum total head

Maximum suction head

Maximum discharge capacity

Maximum self-feed time

Maximum engine speed (with no load)

Fuel consumption

(Approx. at max discharge)

Priming water capacity

Approx. operating hours

(at rated load without refueling)

SPECIFICATIONS

WB20XT2

GX120T2

WB30XT2

GX160T2

GCBNT GCBRT

4 stroke, overhead valve, single cylinder, inclined by 25°

118 cm 3 (7.2 cu–in)

60.0 x 42.0 mm (2.36 x 1.65 in)

8.5

163 cm 3 (9.9 cu–in)

68.0 x 45.0 mm (2.68 x 1.77 in)

9.0

Transistor magneto ignition

B.T.D.C. 20° ± 2 /1,400 min -1 (rpm) B.T.D.C. 18° ± 2 /1,400 min

BPR6ES (NGK)

Forced spray

0.56 liter (0.59 US qt, 0.49 Imp qt)

-1 (rpm)

0.58 liter (0.61 US qt, 0.51 Imp qt)

SAE 10W – 30 API service classification SJ or later

Forced air

Recoil starter

Ignition primary circuit ground

Horizontal type, butterfly valve

Semi-dry type

Mechanical centrifugal

Reed valve type

2.0 liters (0.53 US gal, 0.44 Imp gal) 3.1 liters (0.82 US gal, 0.68 Imp gal)

Regular unleaded gasoline with a pump octane rating 86 or higher

WB20XT2

50 mm (2.0 in)

50 mm (2.0 in)

28 m (92.4 ft)

8 m (26.4 ft)

575 liters (151.9 US gal) /min

110 sec /5 m (16.4 ft)

3,900 min -1

WB30XT2

Self-feed, suction pump

Direct coupled

80 mm (3.1 in)

80 mm (3.1 in)

26 m (85.8 ft)

8 m (26.4 ft)

1,041 liters (275.0 US gal) /min

150 sec /5 m (16.4 ft)

(rpm)

1.0 liters (0.26 US gal) /hr.

3.0 liters (0.79 US gal)

1.9 Hr

1.5 liters (0.40 US gal) /hr.

5.9 liters (1.59 US gal)

2.1 Hr

1-3

SPECIFICATIONS

SPECIFICATIONS

DIMENSIONS AND WEIGHTS

Model

Description code

Type

Overall length

Overall width

Overall height

Dry weight

Operating weight

ENGINE

Model

Engine model

Description code

Type

Displacement

Bore x stroke

Compression ratio

Ignition system

Ignition timing

Spark plug

Lubrication system

Oil capacity

Recommended oil

Cooling system

Starting system

Stopping system

Carburetor

Air cleaner

Governor

Breather system

Fuel tank capacity

Fuel used

WATER PUMP

Model

Type

Drive system

Suction port diameter

Discharge port diameter

Maximum total head

Maximum suction head

Maximum discharge capacity

Maximum self-priming time

Maximum engine speed

(with no load)

Approx. operating hours

(at max discharge)

WB20XT3

WABT

A, C

490 mm (19.3 in)

365 mm (14.4 in)

420 mm (16.5 in)

20 kg (44 lbs)

23 kg (51 lbs)

WB30XT3

WACT

A, C

510 mm (20.1 in)

385 mm (15.2 in)

455 mm (17.9 in)

26 kg (57 lbs)

29 kg (64 lbs)

WB20XT3

GX120T2

WB30XT3

GX160T2

GCBNT GCBRT

4 stroke, overhead valve, single cylinder, inclined by 25°

118 cm 3 (7.2 cu–in)

60.0 x 42.0 mm (2.36 x 1.65 in)

8.5

Transistor magneto ignition

163 cm 3 (9.9 cu–in)

68.0 x 45.0 mm (2.68 x 1.77 in)

9.0

B.T.D.C. 20° ± 2 /1,400 min -1 (rpm)

BPR6ES (NGK)

Forced spray

B.T.D.C. 18° ± 2 /1,400 min -1 (rpm)

0.56 liter (19 oz, 0.49 Imp qt) 0.58 liter (19.5 oz, 0.51 Imp qt)

SAE 10W – 30 API service classification SJ or later

Forced air

Recoil starter

Ignition primary circuit ground

Horizontal type, butterfly valve

Semi-dry type

Mechanical centrifugal

Reed valve type

2.0 liters (0.53 US gal, 0.44 Imp gal) 3.1 liters (0.82 US gal, 0.68 Imp gal)

Regular unleaded gasoline with a pump octane rating 86 or higher

WB20XT3 WB30XT3

Self priming centrifugal pump

Direct coupled

50 mm (2.0 in)

50 mm (2.0 in)

32 m (105.6 ft)

80 mm (3.1 in)

80 mm (3.1 in)

23 m (75.9 ft)

7.5 m (24.7 ft)

620 liters (163.8 US gal) /min

110 sec /5 m (16.5 ft)

1,100 liters (290.6 US gal) /min

3,900 ± 100 min -1 (rpm)

150 sec /5 m (16.5 ft)

1.7 Hr 1.9 Hr

1-2

SPECIFICATIONS

PERFORMANCE CURVES

WB20XT2


80

60

120

100

40

20

0

0 20 40 60 80 100 120

Discharge Capacity (gallons per minute)

140 160

WB30XT2

120

100

80

60

40

20

0

0 50 100 150 200

Discharge Capacity (gallons per minute)

250 300

1-4

PERFORMANCE CURVES

WB20XT3

(feet)

120

100

80

60

40

20

(m)

20

15

10

5

35

30

25

100 200

50.0

300 400

100.0

DISCHARGE CAPACITY

500 600

150.0

700 liters/min

200.0

US gal/min

WB30XT3

(feet) (m)

60

40

80

20

25

20

15

10

5

200

50.0

400

100.0

600

150.0

DISCHARGE CAPACITY

800

200.0

1000

250.0

1200

300.0

liters/min

US gal/min

1-3


DIMENSIONAL DRAWINGS

SPECIFICATIONS

Unit: mm (in)

455 (17.9) (WB20XT2)

510 (20.1) (WB30XT2)

365 (14.4) (WB20XT2)

385 (15.2) (WB30XT2)

1-5

DIMENSIONAL DRAWINGS

Unit: mm (in)

490 (19.3) (WB20XT3)

510 (20.1) (WB30XT3)

1-4

365 (14.4) (WB20XT3)

385 (15.2) (WB30XT3)

MEMO

dummytext

2. SERVICE INFORMATION

2

MAINTENANCE STANDARDS ·····················2-2

TORQUE VALUES ········································2-4

LUBRICATION & SEAL POINTS··················2-5

TOOLS ·························································· 2-6

HARNESS AND TUBE ROUTING ················ 2-8

2-1



MAINTENANCE STANDARDS

WB20XT2

Part

Engine

Cylinder head

Cylinder

Piston

Piston pin

Piston rings

Connecting rod

Crankshaft

Cylinder barrel

Crankcase cover

Valves

Camshaft

Carburetor

Spark plug

Spark plug cap

Ignition coil

Item

Maximum speed (at no load)

Idle speed

Cylinder compression

Warpage

Sleeve I.D.

Skirt O.D.

Piston-to-cylinder clearance

Piston pin bore I.D.

Pin O.D.

Piston pin-to-piston pin bore clearance

Ring side clearance

Ring end gap

Ring width

Top

Second

Top

Second

Oil (side rail)

Top

Second

Small end I.D.

Big end side clearance

Big end I.D.

Big end oil clearance

Crankpin O.D.

Crankshaft runout

Camshaft journal I.D.


Valve clearance

Valve stem O.D.

Valve guide I.D.

Guide-to-stem clearance

Valve guide installation height

Valve seat width

Cam height

IN

IN/EX

Valve spring free length

Valve spring perpendicularity

IN

EX

Camshaft O.D.

Main jet

Pilot screw opening

Float height

Gap

Resistance (20°C/68°F)

Air gap

Primary resistance

Secondary resistance

IN

EX

IN

EX

IN/EX

IN

EX


Standard

3,900 ± 100 min -1 (rpm)

1,400

+ 200

– 150 min -1 (rpm)

0.49 – 0.69 MPa (5.0 – 7.0 kgf/cm 2 , 71 –

100 psi)/600 min -1 (rpm)

–

60.000 – 60.015 (2.3622 – 2.3628)

59.965 – 59.985 (2.3608 – 2.3616)

0.015 – 0.050 (0.0006 – 0.0020)

13.002 – 13.008 (0.5119 – 0.5121)

12.994 – 13.000 (0.5116 – 0.5118)

0.002 – 0.014 (0.0001 – 0.0006)

0.035 – 0.070 (0.0014 – 0.0028)

0.045 – 0.080 (0.0018 – 0.0032)

0.200 – 0.350 (0.0079 – 0.0138)

0.350 – 0.500 (0.0138 – 0.0197)

0.2 – 0.7 (0.01 – 0.03)

0.950 – 0.970 (0.0374 – 0.0382)

0.940 – 0.960 (0.0370 – 0.0378)

13.005 – 13.020 (0.5120 – 0.5126)

0.1 – 0.4 (0.004 – 0.016)

26.020 – 26.033 (1.0244 – 1.0249)

0.040 – 0.063 (0.0016 – 0.0025)

25.970 – 25.980 (1.0224 – 1.0228)

–

14.000 – 14.018 (0.5512 – 0.5519)

Unit: mm (in)

Service limit

–

–

–

14.000 – 14.018 (0.5512 – 0.5519)

0.15 ± 0.02 (0.006 ± 0.001)

0.20 ± 0.02 (0.008 ± 0.001)

5.468 – 5.480 (0.2153 – 0.2157)

5.425 – 5.440 (0.2136 – 0.2142)

5.500 – 5.512 (0.2165 – 0.2170)

0.020 – 0.044 (0.0008 – 0.0017)

0.060 – 0.087 (0.0024 – 0.0034)

4.8 – 5.2 (0.19 – 0.20)

14.048 (0.5531)

–

–

5.318 (0.2094)

5.275 (0.2077)

5.572 (0.2194)

0.10 (0.004)

0.12 (0.005)

–

0.70 – 0.90 (0.028 – 0.035)

30.5 (1.20)

–

27.600 – 27.800 (1.0866 – 1.0945)

27.647 – 27.847 (1.0885 – 1.0963)

13.966 – 13.984 (0.5498 – 0.5506)

27.500 (1.0827)

13.916 (0.5479)

#62

2-1/8 turns out (T2); 1-7/8 turns out (WB20XT3)

13.7 (0.54)

0.70 – 0.80 (0.028 – 0.031)

7.5 – 12.5 k Ω

0.2 – 0.6 (0.01 – 0.02)

0.6 – 0.9 Ω

5.6 – 6.9 k Ω

2.0 (0.08)

29.0 (1.14)

1.5° max.

27.450 (1.0807)

–

–

–

–

–

–

–

–

0.10 (0.004)

60.165 (2.3687)

59.845 (2.3561)

0.12 (0.005)

13.048 (0.5137)

12.954 (0.5100)

0.08 (0.003)

0.15 (0.006)

0.15 (0.006)

1.0 (0.04)

1.0 (0.04)

1.0 (0.04)

0.93 (0.037)

0.92 (0.036)

13.07 (0.515)

1.1 (0.04)

26.066 (1.026)

0.12 (0.005)

25.92 (1.020)

0.10 (0.004)

14.048 (0.5531)

2-2


WB30XT2

Part

Engine

Cylinder head

Cylinder

Piston

Piston pin

Piston rings

Connecting rod

Crankshaft

Cylinder barrel

Crankcase cover

Valves

Camshaft

Carburetor

Spark plug

Spark plug cap

Ignition coil

Item

Maximum speed (at no load)

Idle speed

Cylinder compression

Warpage

Sleeve I.D.

Skirt O.D.

Piston-to-cylinder clearance

Piston pin bore I.D.

Pin O.D.

Piston pin-to-piston pin bore clearance

Ring side clearance

Ring end gap

Ring width

Top

Second

Top

Second

Oil (side rail)

Top

Second

Small end I.D.

Big end side clearance

Big end I.D.

Big end oil clearance

Crankpin O.D.

Crankshaft runout



Valve clearance

Valve stem O.D.

Valve guide I.D.

Guide-to-stem clearance

Valve guide installation height

Valve seat width

IN

IN

EX

Valve spring free length

Valve spring perpendicularity

IN/EX Cam height

Camshaft O.D.

Main jet

Pilot screw opening

Float height

Gap

Resistance (20°C/68°F)

Air gap

Primary resistance

Secondary resistance

IN

EX

IN

EX

IN/EX

IN

EX


Standard

3,900 ± 100 min -1 (rpm)

1,400

+ 200

– 150 min -1 (rpm)

0.49 – 0.69 MPa (5.0 – 7.0 kgf/cm

100 psi)/600 min -1 (rpm)

–

68.000 – 68.015 (2.6772 – 2.6778)

67.985 – 67.995 (2.6766 – 2.6770)

0.005 – 0.030 (0.0002 – 0.0012)

18.002 – 18.008 (0.7087 – 0.7090)

17.994 – 18.000 (0.7084 – 0.7087)

2 , 71 –

0.002 – 0.014 (0.0001 – 0.0006)

0.060 – 0.095 (0.0024 – 0.0037)

0.045 – 0.080 (0.0018 – 0.0032)

0.200 – 0.350 (0.0079 – 0.0138)

0.350 – 0.500 (0.0138 – 0.0197)

0.10 – 0.35 (0.004 – 0.014)

0.925 – 0.945 (0.0364 – 0.0372)

0.940 – 0.960 (0.0370 – 0.0378)

18.005 – 18.020 (0.7089 – 0.7094)

0.1 – 0.4 (0.004 – 0.016)

30.020 – 30.033 (1.1819 – 1.1824)

0.040 – 0.063 (0.0016 – 0.0025)

29.970 – 29.980 (1.1799 – 1.1803)

–

14.000 – 14.018 (0.5512 – 0.5519)

14.000 – 14.018 (0.5512 – 0.5519)

0.08 ± 0.02 (0.003 ± 0.001)

0.10 ± 0.02 (0.004 ± 0.001)

5.468 – 5.480 (0.2153 – 0.2157)

5.425 – 5.440 (0.2136 – 0.2142)

5.500 – 5.512 (0.2165 – 0.2170)

0.020 – 0.044 (0.0008 – 0.0017)

0.060 – 0.087 (0.0024 – 0.0034)

4.8 – 5.2 (0.19 – 0.20)

0.70 – 0.90 (0.028 – 0.035)

0.90 – 1.10 (0.035 – 0.043)

30.5 (1.20)

–

27.603 – 27.703 (1.0867 – 1.0907)

13.966 – 13.984 (0.5498 – 0.5506)

#68

1-7/8 turns out

13.7 (0.54)

0.70 – 0.80 (0.028 – 0.031)

7.5 – 12.5 k Ω

0.2 – 0.6 (0.01 – 0.02)

0.6 – 0.9 Ω

5.6 – 6.9 k Ω

Unit: mm (in)

Service limit

–

–

–

14.048 (0.5531)

–

–

5.318 (0.2094)

5.275 (0.2077)

5.572 (0.2194)

0.10 (0.004)

0.12 (0.005)

–

2.0 (0.08)

2.0 (0.08)

29.0 (1.14)

1.5° max.

27.450 (1.0807)

13.916 (0.5479)

–

–

–

–

–

–

–

–

0.10 (0.004)

68.165 (2.6837)

67.845 (2.6711)

0.12 (0.005)

18.048 (0.7105)

17.954 (0.7068)

0.08 (0.003)

0.15 (0.006)

0.15 (0.006)

1.0 (0.04)

1.0 (0.04)

1.0 (0.04)

0.905 (0.0356)

0.92 (0.036)

18.07 (0.711)

1.1 (0.04)

30.066 (1.1837)

0.12 (0.005)

29.92 (1.178)

0.10 (0.004)

14.048 (0.5531)

2-3


TORQUE VALUES

ENGINE TORQUE VALUES

Item

Crankcase cover bolt (WB20XT2 /GX120T2)

Crankcase cover bolt (WB30XT2 /GX160T2)

Cylinder head bolt

Engine oil drain plug bolt

Connecting rod bolt (WB20XT2 /GX120T2)

Connecting rod bolt (WB30XT2 /GX160T2)

Rocker arm pivot bolt

Rocker arm pivot lock nut

Spark plug

Oil level switch joint nut

Flywheel nut

Fuel tank nut/bolt

Fuel tank joint

Air cleaner elbow nut

Air cleaner cover wing nut

Muffler nut

Recoil starter center screw

Fuel strainer cup

WATER PUMP TORQUE VALUES

Item

Impeller

STANDARD TORQUE VALUES

Item

Screw

Bolt and nut

Flange bolt and nut

SH (Small head) flange bolt

CT (Cutting threads) flange bolt (Retightening)

Tread Dia. (mm)

M6 x 1.0

M8 x 1.25

M8 x 1.25

M10 x 1.25

M7 x 1.0

M6 x 1.0

M8 x 1.25 (Special bolt)

M6 x 0.5 (Special nut)

M14 x 1.25 (Special)

M10 x 1.25


M6 x 1.0

M10 x 1.25

M6 x 1.0


M8 x 1.25

M6 x 1.0 (Special bolt)

M24 x 1.0

Tread Dia. (mm)

M16 x 1.5

4 mm

5 mm

6 mm

5 mm

6 mm

8 mm

10 mm

12 mm

5 mm

6 mm

8 mm

10 mm

6 mm

5 mm

6 mm

Tread Dia. (mm)


N·m

2

9

1.2

24

18

10

75

10

5.4

3.9

12

9.8

24

10

12

24

24

18

Torque values kgf·m

0.2

0.9

0.1

2.4

1.8

1.0

7.6

1.0

0.6

0.4

1.2

1.0

2.4

1.0

1.2

2.4

2.4

1.8

lbf·ft

1.5

6.6

0.9

18

13

7

55

7

4.0

2.9

9

7.2

18

7

9

18

18

13

N·m

25

Torque values kgf·m

2.5

lbf·ft

18

40

9

5.4

12

54

5.3

12

23

N·m

2.1

4.3

9

5.3

10

22

34

Torque values

4.1

0.9

0.6

1.2

5.5

0.5

1.2

2.3

kgf·m

0.2

0.4

0.9

0.5

1.0

2.2

3.5

30

6.6

4.0

9

40

3.9

9

17 lbf·ft

1.5

3.2

6.6

3.9

7

16

25

2-4


LUBRICATION & SEAL POINTS

ENGINE

Location

Crankshaft pin and gear teeth

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 profile

Valve lifter pivot, pivot end and slipper surface

Valve stem sliding surface and stem end

Valve rocker arm tappet surface and pivot

Rocker arm pivot threads and pivot

Governor weight holder sliding surface and gear

Governor holder shaft journal

Governor arm shaft journal

Flywheel nut threads and seating surface

Cylinder head bolt threads and seating surface

Oil seal lips

O-ring

Control lever sliding surface

Recoil starter case pulley sliding surface

Recoil starter ratchet sliding surface

Recoil starter spring retainer inside

Camshaft cam profile

Recoil starter center screw threads

Limiter cap inside

Engine oil

Material

Multi-purpose grease

Use molybdenum oil solution

(mixture of the engine oil and molybdenum grease in a ratio of 1:1)

Hondalock 1, or equivalent

Hondalock 3, LOCTITE or equivalent

® 638,

WATER PUMP

Location

Mechanical seal and casing mating surface

Material

Sealant (Hondabond HT or equivalent)


Remarks

When installing a new camshaft

Remarks

2-5

SERVICE INFORMATION WB20XT2•WB30XT2

TOOLS

SPECIAL TOOLS

Special tools used in this manual can be ordered using normal American Honda parts ordering procedures.

Jet cleaner set

07JPZ-001010B

Float level gauge

07401-0010000

Valve guide driver, 5.5 mm

07742-0010100 or 07JPZ-001010A

Driver

07749-0010000

Attachment, 37 x 40 mm

07746-0010200


07746-0010400

Pilot, 25 mm

07746-0040600


07946-6920100

Pilot, 22 mm

07746-0041000


07746-0010100

Mechanical seal attachment

07948-9540000

Valve guide reamer, 5.510 mm

07984-2000001

Water pump vacuum tester

07APJ-YB3A100

20

30

0.8

1

0.6

0.4

0

0.2

0

" Hg

2-6


COMMERCIALLY AVAILABLE TOOLS


Tool name

Fuel line clip pliers

Two-jaw puller

Valve seat cutter, 31°



Solid pilot (short) 5.5 mm

Accessory kit

T-wrench

Adapter, 1/2"-3/8"

Tool number

HCP6A

OTC1035

NWYCU115

NWYCU122

MWYCU111

NWYPM10055SH

NWYKACC246

NWYTW505

NWYTW503-1

Carburetor removal

Flywheel removal

Application

Valve seat reconditioning

There are two convenient ways to order: online or by toll-free phone.

• To order online, go to the iN: SERVICE>Tools>Tool and Equipment Program>Online Catalog, and then search by model number.

• To order by phone, call 1-888-424-6857.

Customer service representatives are available from 7:30 AM until 7:00 PM CT, Monday through Friday.

2-7


HARNESS AND TUBE ROUTING

WB20XT2:

CARBURETOR INSULATOR

ENGINE WIRE

HARNESS

HIGH-TENSION CORD

WB30XT2:

HIGH-TENSION CORD

ENGINE WIRE

HARNESS


CYLINDER BARREL RIBS

CYLINDER BARREL RIBS

TO ENGINE

STOP

SWITCH


CORD HOOK

IGNITION COIL CONNECTOR

2-8


WB20XT2:

FAN COVER CLAMP

HIGH-TENSION CORD

WB30XT2:



BREATHER TUBE

CARBURETOR

INSULATOR

FUEL TUBE

2-9


ENGINE STOP SWITCH


HARNESS CLIP

ENGINE WIRE

HARNESS

CONNECTOR

OIL LEVEL SWITCH

CONNECTOR

OIL ALERT UNIT

CONNECTOR

ENGINE STOP

SWITCH WIRE

ENGINE WIRE

HARNESS

WB30XT2: ENGINE WIRE HARNESS

CLAMP

OIL LEVEL SWITCH

CONNECTOR

OIL LEVEL SWITCH

CONNECTOR

OIL ALERT

UNIT WIRES

To ignition coil

To Oil Alert unit

Y Bl

Bl

ENGINE STOP

SWITCH WIRE

ENGINE WIRE

HARNESS

CONNECTOR

OIL ALERT UNIT

CONNECTOR

OIL LEVEL

SWITCH WIRE

ENGINE WIRE

HARNESS

CONNECTOR

Y

Bl Y

HARNESS CLIP

To engine stop switch

To oil level switch

OIL ALERT UNIT

CONNECTOR

2-10

dummytext

3. MAINTENANCE

3

MAINTENANCE SCHEDULE························3-2

ENGINE OIL LEVEL CHECK/CHANGE ·······3-3

AIR CLEANER CHECK/CLEANING ·············3-4

SPARK PLUG CHECK/ADJUSTMENT ········3-5

SPARK PLUG REPLACEMENT ···················3-5

SEDIMENT CUP CLEANING ························3-6

IDLE SPEED CHECK/ADJUSTMENT ··········3-6

VALVE CLEARANCE

CHECK/ADJUSTMENT ································ 3-7

COMBUSTION CHAMBER CLEANING ······· 3-9

FUEL TANK AND FILTER CLEANING ········ 3-9

FUEL TUBE CHECK ··································· 3-10

IMPELLER CHECK ····································· 3-10

IMPELLER CLEARANCE CHECK ············· 3-11

PUMP INLET VALVE CHECK ···················· 3-12

3-1

MAINTENANCE

MAINTENANCE

MAINTENANCE SCHEDULE


Item

REGULAR SERVICE PERIOD (2)

Perform at every indicated month or operating hour interval,

Each use whichever comes first.

First month or

20 hrs.

Every

3 months or

50 hrs.

Every

6 months or

100 hrs.

Every year or

300 hrs.

Engine oil

Air cleaner

Spark plug

Check-Level

Change

Check

Clean

Check-Adjust

Replace

Clean

(1)

Spark arrester

(applicable types)

Sediment cup

Idle speed

Valve clearance

Combustion chamber

Fuel tank and filter

Fuel tube

Impeller

Impeller clearance

Pump inlet valve

Clean

Check-Adjust

Check-Adjust

Clean

Clean

Check

Check

Check

Check

After every 500 hrs.

Every 2 years (Replace if necessary)

(1) Service more frequently when used in dusty areas.

(2) For commercial use, log hours of operation to determine proper maintenance intervals.

Refer to page

3-3

3-3

3-4

3-4

3-5

3-5

–

3-6

3-6

3-7

3-9

3-9

3-10

3-10

3-11

3-12

3-2


ENGINE OIL LEVEL CHECK/CHANGE

CHECK

Place the water pump on a level surface.

Remove the oil filler cap (1) and verify the oil level is at the top of the oil filler neck (2).

If the oil level is low, fill with recommended oil to the top

of the oil filler neck (page 3-3).

Check that the oil filler packing (3) is in good condition; replace it if necessary.

Install and tighten the oil filler cap securely.

(1)

MAINTENANCE

(2)

(3)

CHANGE

Place the water pump on a level surface and place a suitable container under the drain plug bolt (1).

Remove the oil filler cap (2), drain plug bolt, and drain plug washer (3), and drain the oil into a suitable container.

Please dispose of used oil in a manner that is compatible with the environment. We suggest you take used oil in a sealed container to your local recycling center or service station for reclamation. Do not throw it in the trash, pour it on the ground, or pour it down a drain.

(2)

Used engine oil contains substances that have been identified as carcinogenic. If repeatedly left in contact with the skin for prolonged periods, it may cause skin cancer. Wash your hands thoroughly with soap and water as soon as possible after contact with used engine oil.

Install the drain plug bolt with a new drain plug washer and tighten it to the specified torque.

TORQUE: 18 N·m (1.8 kgf·m, 13 lbf·ft)

Add the specified amount of recommended oil into the engine.

ENGINE OIL CAPACITY:

WB20XT2: 0.56 liter (0.59 US qt, 0.49 Imp qt)

WB30XT2: 0.58 liter (0.61 US qt, 0.51 Imp qt)

RECOMMENDED OIL:

SAE 10W-30 API service classification SJ or later

After adding the oil, check the oil level.

Check that the oil filler packing (4) is in good condition, replace it if necessary.

Install and tighten the oil filler cap securely.

Make sure there are no oil leaks.

(4)

(1) (3)

SAE VISCOSITY GRADES

AMBIENT TEMPERATURE

3-3

MAINTENANCE

AIR CLEANER CHECK/CLEANING

CHECK

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.

(3)

Operating the engine without the air filter or with the filter installed loosely will allow dirt to enter the engine, causing rapid engine wear. Install the air filter securely.

Remove the following:

– Wing nut (1)

– Air cleaner cap (2)

– Air cleaner cover (3)

– Air cleaner element (4)

If the element is dirty, clean it (page 3-4).

Carefully check the element for holes or tears and replace if damaged.

Installation is in the reverse order of removal

(page 6-5).

(2)


CLEANING

Clean the element (1) in warm soapy water, rinse, and allow to dry thoroughly, or clean with a non-flammable solvent and allow to dry thoroughly.

Dip the element in clean engine oil, and squeeze out all the excess oil.

Excess oil will restrict air flow through the foam element and may cause the engine to smoke at startup.

(1)

Wash

Squeeze and dry

Dip

(1)

(4)

Squeeze thoroughly

3-4


SPARK PLUG CHECK/ADJUSTMENT

Remove the spark plug (page 3-5).

Check the following and replace if necessary.

– Insulator (1) and sealing washer (2) for damage

– Center electrode (3) and side electrode (4) for wear

– Burning condition, coloration

RECOMMENDED SPARK PLUG:

BPR6ES (NGK)

Measure the plug gap with a wire-type feeler gauge.

PLUG GAP: 0.70 – 0.80 mm (0.028 – 0.031 in)

If the measurement is out of the specification, adjust by bending the side electrode.

Install the spark plug (page 3-5).

SPARK PLUG REPLACEMENT

REMOVAL

The engine and the muffler become very hot during operation and remain hot for a while after stopping the engine. Be careful not to touch the muffler while it is hot. Allow it to cool before proceeding.

Disconnect the spark plug cap (1) and remove the spark plug (2).

Clean around the spark plug base with compressed air before removing the spark plug, and be sure that no debris is allowed to enter into the combustion chamber.

INSTALLATION

Install and hand tighten the spark plug to the cylinder head.

RECOMMENDED SPARK PLUG:

BPR6ES (NGK)

Tighten the spark plug to the specified torque.


Connect the spark plug cap.

(1)

(1)

(2)

MAINTENANCE

(2)

(3)

(4)

3-5

MAINTENANCE

SEDIMENT CUP CLEANING

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 (1) to the OFF position.


– Sediment cup (2)

– O-ring (3)

– Cup filter (4)

Clean the sediment cup and the cup filter with nonflammable solvent and allow them to dry thoroughly.

Install the cup filter while aligning it with the tip with the groove of the carburetor and cup filter tab (5) with the mark (6) of the carburetor.

Install a new O-ring and sediment cup.

Tighten the sediment cup to the specified torque.

TORQUE: 3.9 N·m (0.4 kgf·m, 2.9 lbf·ft)

Check the installation part of the sediment cup for any sign of fuel leakage.

(6)

(4)

(3)

IDLE SPEED CHECK/ADJUSTMENT

Ensure the governor arm and governor arm shaft are

installed correctly (page 7-4).

Use a tachometer with graduations of 50 min change.

-1 (rpm) or smaller that will accurately indicate 50 min -1 (rpm)

Fill the pump housing with water before starting.

Start the engine and allow it to warm up to normal operating temperature.

Turn the throttle stop screw (1) to obtain the specified idle speed.

IDLE SPEED: 1,400

+ 200

– 150

min -1 (rpm)

(5)


(1)

Align

(2)

(1)

3-6


VALVE CLEARANCE CHECK/

ADJUSTMENT

Inspect and adjust the valve clearance while the engine is cold.

CHECK

Disconnect the spark plug cap (1) and remove the following:

– Breather tube (2)

– Head cover bolt (6 x 12 mm) (3)

– Head cover (4)

– Head cover packing (5)

(4) (1)

MAINTENANCE

(2)

(3)

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 mark (1) on the starter pulley (2) will align with the top hole (3) on the recoil starter case (4).

If the exhaust valve is open, use the recoil starter to turn the crankshaft one additional turn and align the triangle mark on the starter pulley with the top hole on the recoil starter case again.

Pull slowly.

(4)

(1)

(5)

(3)

(2)

3-7

MAINTENANCE

Insert a thickness gauge (1) between the valve rocker arm (2) and valve stem (3) to measure the valve clearance.

VALVE CLEARANCE:

WB20XT2:

IN: 0.15 ± 0.02 mm (0.006 ± 0.001 in)

EX: 0.20 ± 0.02 mm (0.008 ± 0.001 in)

WB30XT2:

IN: 0.08 ± 0.02 mm (0.003 ± 0.001 in)

EX: 0.10 ± 0.02 mm (0.004 ± 0.001 in)

If adjustment is necessary, proceed as follows.

(1)


(3) (2)

(2)

(3)

ADJUSTMENT

Hold the rocker arm pivot (1) and loosen the lock nut

(2).

Insert a thickness gauge (3) between the valve rocker arm and the valve stem.

Adjust by turning the adjusting screw until there is a slight drag on the feeler gauge.

VALVE CLEARANCE:

WB20XT2:

IN: 0.15 ± 0.02 mm (0.006 ± 0.001 in)

EX: 0.20 ± 0.02 mm (0.008 ± 0.001 in)

WB30XT2:

IN: 0.08 ± 0.02 mm (0.003 ± 0.001 in)

EX: 0.10 ± 0.02 mm (0.004 ± 0.001 in)

Hold the rocker arm pivot and retighten the lock nut to the specified torque.


Recheck the valve clearance, and if necessary, readjust the clearance.

Replace the head cover packing with a new one and install the removed parts in the reverse order of removal.

(3)

Route the high-tension cord and breather tube properly

(page 2-8).

(1)

(2)

3-8


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.

(1)

MAINTENANCE

FUEL TANK AND FILTER CLEANING





Remove the fuel tank (page 6-3).

Remove the fuel tank joint (1) and O-ring (2) from the fuel tank (3).

Clean the fuel tank joint and fuel tank with nonflammable solvent, and allow them to dry thoroughly.

Check the screen of the fuel tank joint for clogs or damage, replace if necessary.

Install a new O-ring to the fuel tank joint and install them to the fuel tank.

Tighten the fuel tank joint to the specified torque.

TORQUE: 2 N·m (0.2 kgf·m, 1.5 lbf·ft)

Install the fuel tank (page 6-3).

After installation, check for any signs of fuel leakage.

(2)

(1)

(3)

3-9

MAINTENANCE

FUEL TUBE CHECK





Check the fuel tube (1) for deterioration, cracks or signs of leakage.

Replace if necessary.

When checking, WB30XT2 remove the fan cover (page

5-2).

(1)


IMPELLER CHECK

Remove the impeller cover (1) (page 10-5).

Check the impeller (2) for damage or contamination and replace if necessary.

(2)

(1)

3-10


IMPELLER CLEARANCE CHECK

Remove the impeller cover (1) (page 10-5).

Measure the depth of the impeller cover by using the depth gauge or vernier caliper.

MAINTENANCE

Measure the height of the impeller (1) vanes from the rib (2) of the end plate (3).

(1)

(3)

(2) (1)

3-11

MAINTENANCE

Subtract the height of the impeller (1) from the depth of the impeller cover (2) to obtain the impeller clearance

(3).

IMPELLER CLEARANCE:

WB20XT2:

0.30 – 0.70 mm (0.012 – 0.028 in)

WB30XT2:

0.50 – 0.90 mm (0.020 – 0.035 in)

If not, adjust clearance by adding or removing adjuster

shims (4) (page 10-7).


(2)

(1)

(3)

(4)

IMPELLER

PUMP INLET VALVE CHECK

Remove the inlet pipe (1) (page 10-3).

Check the pump inlet valve (2) for damage or contamination and replace if necessary.

IMPELLER COVER

(2)

(1)

3-12

MAINTENANCE

IMPELLER CLEARANCE CHECK

Remove the volute case [1] ( page 10-3 ).

Measure the depth of the impeller cover by using the depth gauge or vernier caliper.

Measure the height of the impeller vanes [1] from the casing cover [2].

[1]

[2]

[1]

3-2

Subtract the height of the impeller [1] from the depth of the volute case [2] to obtain the impeller clearance [3].

IMPELLER CLEARANCE:

WB20XT3:

0.30 – 0.70 mm (0.012 – 0.028 in)

WB30XT3:

0.50 – 0.90 mm (0.020 – 0.035 in)

If not, adjust clearance by adding or removing adjuster

shims [4] ( page 10-5 ).

[2]

[1]

[3]

[4]

IMPELLER

VOLUTE CASE

3-3

dummytext

4. TROUBLESHOOTING

BEFORE TROUBLESHOOTING···················4-2

ENGINE TROUBLESHOOTING····················4-2

WATER PUMP TROUBLESHOOTING········· 4-6

4

4-1

TROUBLESHOOTING WB20XT2•WB30XT2

TROUBLESHOOTING

BEFORE 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 pump case and volute case, and check the pump condition.

Jammed

Not jammed

Remove the spark plug and check for water or oil in the combustion chamber.

Normal

Remove the recoil starter (page 9-2) and check

whether the engine cranks.

Cranks

Inspect the recoil starter (page 9-6).

Abnormal

Remove any foreign materials.

Disassemble the cylinder head and replace the

faulty part(s) (page 12-3).

Cannot be cranked

Disassemble the cylinder barrel and replace

the faulty part(s) (page 13-4).

Abnormal

Replace the faulty part(s).

4-2


ENGINE WON’T START

• Check the oil level before troubleshooting (page 3-3).

Loosen the carburetor drain screw and check the

fuel flow from the fuel tank (page 6-3).

No fuel

Fuel

Perform the spark test (page 8-8).

No spark

Spark

Check the cylinder compression (page 12-5).

TROUBLESHOOTING

Check for clogged fuel tank joint or fuel tube

(page 3-9, 3-10).

Perform the IGNITION SYSTEM

TROUBLESHOOTING (page 8-2).

Compression is too high

Check the valve clearance (page 3-7) and then

perform the cylinder compression test. If the cylinder compression is too high, remove carbon

deposits in the combustion chamber (page 3-9).

Check the decompressor operation of the

camshaft (page 13-12).

Compression is too low

Check the valve clearance (page 3-7), and then

perform the cylinder compression test.

If the cylinder compression is too low, perform a leak down test.

If the leak down test reveals excessive leakage into the crankcase, inspect the piston, cylinder, and rings for wear.

If the test reveals leakage out the intake port, inspect the intake valve for proper sealing.

If the test reveals leakage out the exhaust port, inspect the exhaust valve for proper sealing.

Check the spark plug (page 3-5).

Dry

Disassemble the carburetor to clean the carburetor parts, jets and nozzles

(page 6-7, 6-8).

Wet

If spark plug is correct, clean and dry the electrodes and then restart the engine, taking care that the choke valve is not closed too much.

If the engine does not start and the electrodes are wet again, check the carburetor float valve

(page 6-8).

4-3

TROUBLESHOOTING

ENGINE SURGES

Partially close the choke. Does the engine speed stabilize?

Yes No


Check the air cleaner element (page 3-4).

Clogged or saturated

Clean or replace the air cleaner element

(page 3-4).

Clean

Check the spark plug (page 3-5).

Abnormal Inspect the spark plug and adjust the spark plug

gap (page 3-5). Replace if necessary (page 3-5).

Normal

Check that the governor system is installed

correctly (page 7-2).

Normal

Check the ignition coil air gap (page 8-7).

Normal

Check the ignition coil (page 8-9).

Normal

Check the valve clearance (page 3-7).

Normal

Check the cylinder compression (page 12-5).

Abnormal

Abnormal

Abnormal

Adjust or replace the faulty part(s).

Adjust the ignition coil air gap (page 8-7).

Replace the ignition coil and recheck.

Abnormal

Compression is too high

Adjust the valve clearance (page 3-7).

Compression is too low

Check for carbon deposits in the combustion

chamber (page 3-9).

Check that the cylinder head bolts are correctly

torqued (page 12-3).

Check for defective cylinder head gasket, valves,

or valve seats (page 12-3, 12-6, 12-7).

Check for worn piston, piston rings, or cylinder

(page 13-6).

4-4

Check the carburetor for any obstructions

(page 6-7).

Clean

Check for secondary air leak.

Clogged

Air leaking

Disassemble and clean the carburetor

(page 6-7, 6-8).

Check around the air intake joint and carburetor; replace the insulator and/or gasket if necessary.


ENGINE DOES NOT STOP WHEN

ENGINE STOP SWITCH IS TURNED OFF

Check the engine stop switch (page 8-10).

Abnormal

Normal

Check the wire harness connecting the engine stop switch and the ignition coil for open or short circuit.

Continuity

Check the ignition coil primary side (page 8-9).

Replace the ignition coil if abnormalities are found, and recheck.

No continuity

ENGINE DOES NOT STOP WHEN ENGINE OIL

LEVEL IS LOW

Check the oil level switch (page 8-9).

Abnormal

Normal

Check the Oil Alert ®

unit (page 8-11).

Abnormal

Normal

Check the wire harness connecting the oil level switch and ignition coil for open or short circuit.

Continuity

Check the ignition coil primary side (page 8-9).

Replace the ignition coil if abnormalities are found, and recheck.

No continuity

TROUBLESHOOTING

Replace the engine stop switch (page 8-6).

Replace the engine wire harness.

Replace the oil level switch (page 8-6).

Replace the Oil Alert unit (page 8-7).


4-5

TROUBLESHOOTING

WATER PUMP TROUBLESHOOTING

Pump will not prime Priming water too low

Mechanical seal damaged

Inlet valve damaged

Suction hose damaged

Air leak

Mounting faulty

Strainer clogged

Strainer damaged

SERVICE BULLETIN #8

Discharge amount or pressure too low


Increase.

Replace (page 10-8).

Replace (page 10-3, 10-4).


Tighten parts.

Correct.

Clean out.


Air leak

Mounting faulty

Strainer clogged

Impeller clearance excessive

Pump RPM too low

Lift head too high

Suction/discharge hoses too small and/or too long.

Tighten parts.

Correct.

Clean out.

Adjust (page 3-11).

Adjust throttle or governor

(page 3-6, 7-4).

Correct.

Correct.

4-6


Self-feed time too long Priming water too low

Mechanical seal damaged

Inlet valve damaged

Suction hose damaged

Air leak

Pump RPM too high

Strainer clogged

Lift head too high

Suction hose too long.

Noise or vibration (cavitation) Mounting faulty

Strainer damaged

Suction lift head too high

Suction hose too small and/or too long.

TROUBLESHOOTING

Increase.

Replace (page 10-8).



Tighten parts.

Adjust throttle or governor

(page 3-6, 7-4).

Clean out.

Correct.

Correct.

Correct.


Correct.

Correct.

4-7

MEMO

dummytext

FAN COVER REMOVAL/INSTALLATION····5-2

5. COVER

5

5-1

COVER

COVER

FAN COVER REMOVAL/INSTALLATION

Remove the fuel tube from the clamp (WB20XT2 only).

When installing, route the tube and wires properly (page 2-8).

WB20XT2 only:

FUEL TUBE

CLAMP

ENGINE WIRE HARNESS CONNECTOR


FAN COVER

INSTALLATION:

Be careful not to clip the fuel tube.

BOLT (6 x 12 mm) (4)

OIL ALERT UNIT CONNECTOR

5-2

dummytext

6. FUEL SYSTEM

TOOLS···························································6-2

FUEL TANK

REMOVAL/INSTALLATION··························6-3

AIR CLEANER


CARBURETOR


CARBURETOR

DISASSEMBLY/ASSEMBLY ························6-7

CARBURETOR BODY CLEANING ·············· 6-8

CARBURETOR INSPECTION ······················ 6-8

PILOT SCREW REPLACEMENT ················· 6-9

CHOKE REPLACEMENT ··························· 6-10

CARBURETOR STUD BOLT

REPLACEMENT ········································· 6-10

6

6-1

FUEL SYSTEM

TOOLS

FUEL SYSTEM

Jet cleaner set

07JPZ-001010B

Float level gauge

07401-0010000 or 07JPZ-001010A


6-2


FUEL TANK REMOVAL/INSTALLATION





Remove the fan cover (WB30XT2 only) (page 5-2).

Place a suitable container under the carburetor.

Turn the fuel valve lever (1) to the ON position.

Loosen the drain screw (2) and drain the fuel.

When installing, route the tube properly (page 2-8).

FUEL FILLER CAP

(C type)

FUEL FILLER CAP PACKING

(C type)

CHECK:

Check for deterioration or cracks.

O-RING

FUEL TANK JOINT

2 N·m (0.2 kgf·m, 1.5 lbf·ft)

CHECK:

Check the screen of the fuel tank joint for clogs or damage.

BOLT (6 x 29 mm)

10 N·m (1.0 kgf·m, 7 lbf·ft)

FUEL SYSTEM

(1)

(2)

FUEL FILLER CAP

(A type)

FUEL FILLER CAP PACKING

(A type)

CHECK:


FUEL FILTER HOLDER

(A type)

FUEL TANK

NUT (6 mm) (2)

10 N·m (1.0 kgf·m, 7 lbf·ft)

FUEL TUBE

CHECK:


6-3

FUEL SYSTEM

FUEL FILTER HOLDER

REMOVAL/INSTALLATION

(A 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. If necessary, clean it using low-pressure compressed air.

Install the fuel filter holder into the fuel filler neck and align the cutouts.

Set the fuel filler cap to the fuel filler neck by aligning the projections (5) of the cap with the cutouts of the fuel filler neck and fuel filter holder and then turn the fuel filler cap.

(3)

(5)


(1)

(2)

(4)

6-4


AIR CLEANER


When removing air cleaner elbow, remove the engine (WB20XT2 only) (page 11-2).

WING NUT

1.2 N·m (0.1 kgf·m, 0.9 lbf·ft)

CARBURETOR SPACER

INSTALLATION:

Before installing, check for damage.

Note the installation direction.

FUEL SYSTEM

AIR CLEANER CAP

Viewed from air cleaner side

BOLT (6 x 20 mm)

AIR CLEANER COVER

COLLAR

AIR CLEANER

ELEMENT

AIR CLEANER GRID

BREATHER TUBE

AIR CLEANER COLLAR (2)

AIR CLEANER ELBOW

REMOVAL/INSTALLATION:

Remove and install the air cleaner elbow with the fuel valve lever in the OFF position and the choke lever in the CLOSE position.

Before installation, clean the inside of the air cleaner elbow.

AIR CLEANER ELBOW NUT (6 mm) (2)

9 N·m (0.9 kgf·m, 6.6 lbf·ft)

6-5

FUEL SYSTEM

CARBURETOR







Remove the air cleaner (page 6-5).

Set a commercially available tube clamp HCP6A on the fuel tube.

Loosen the drain screw of the carburetor to drain the fuel completely (page 6-3).

FUEL TUBE

GOVERNOR ROD/ THROTTLE RETURN SPRING


Pull the carburetor to a point where the groove (1) of the throttle arm lines up with the governor rod (2), and then lift the governor rod out of the hole of the throttle arm and unhook the throttle return spring (3).

(2)

(1)

(3)

HCP6A (Commercially available)

CARBURETOR PACKING

TUBE CLIP

INSULATOR PACKING


INSTALLATION:

Before installing, clean the passage (1) thoroughly with compressed air.

Install the carburetor insulator with the vent groove facing toward the carburetor.

After installing, clamp the high-tension cord (2) and fuel tube (3) to the carburetor insulator.

WB20XT2: WB30XT2:

CARBURETOR

(2)

(1)

(2)

(1)

(3)

6-6

DRAIN SCREW


CARBURETOR DISASSEMBLY/ASSEMBLY





FUEL SYSTEM

To prevent serious eye injury, always wear safety goggles or other eye protection when using compressed air.

Remove the carburetor (page 6-6).

Before disassembly, clean the outside of the carburetor.

PILOT JET SET

ASSEMBLY:

Before installing, clean thoroughly with the jet cleaning special tool and low-pressure compressed air.

Lightly lubricate the O-ring

(1) to ensure easy installation into the carburetor body.

(1)

O-RING

THROTTLE STOP SCREW

NOTE 1:

SCREW

(3 x 6 mm) (2)

CHOKE LEVER

MAIN NOZZLE

ASSEMBLY:


UPPER

SIDE

PILOT SCREW

NOTE 2:

LIMITER CAP

LEVER SETTING PLATE

VALVE LEVER

SPRING

FUEL VALVE LEVER

FUEL VALVE

PACKING

CHECK:


SPRING PIN

CARBURETOR BODY

CUP FILTER

NOTE 3:

MAIN JET

NOTICE:

Tampering is a violation of Federal and California Law.

ASSEMBLY:


UPPER

SIDE

FLOAT

O-RING

SEDIMENT CUP

3.9 N·m (0.4 kgf·m, 2.9 lbf·ft)

FLOAT CHAMBER

ASSEMBLY:

Install the float chamber to the carburetor body at an angle as shown.

0 – 30°

FLOAT PIN

O-RING

FLOAT VALVE

FLOAT VALVE SPRING

SET BOLT GASKET

DRAIN SCREW GASKET

NOTE 1

NOTE 2

NOTE 3

SET BOLT

IDLE SPEED ADJUSTMENT

PILOT SCREW REPLACEMENT/INSTALLATION

CUP FILTER REMOVAL/INSTALLATION

DRAIN SCREW

page 3-6

page 6-9

page 3-6

6-7

FUEL SYSTEM

CARBURETOR BODY CLEANING

To prevent serious eye injury, always wear safety goggles or other eye protection when using compressed air.

• Some commercially available chemical cleaners are very caustic. These cleaners may damage plastic parts such as the O-ring, the float, and the float seat of the carburetor. Check the container for 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 (206 kPa (2.11 kgf/cm 2 , 30 psi) or less) when cleaning passages and ports.

Clean the carburetor body with non-flammable solvent.

Clean thoroughly the following passages and ports with low-pressure compressed air.

– Pilot screw hole (1)

– Pilot jet hole (2)

– Pilot air jet (3)

– Main air jet (4)

– Transition ports (5)

– Pilot outlet (6)

– Main nozzle holder (7)

– External vent port (8)

– Internal vent port (9)


(8)

CARBURETOR INSPECTION

FLOAT LEVEL HEIGHT

Place the carburetor in the position as shown. Measure the distance between the float top and carburetor body when the float just contacts the seat without compressing the float valve spring.

TOOL:

Float level gauge (1) 07401-0010000

FLOAT HEIGHT: 13.7 mm (0.54 in)

If the measured float height is out of specification,

check the float valve and float valve spring (page 6-9).

If the float valve and float valve spring are normal,

replace the float (page 6-7).

6-8

(1)

(2)

(7)

(5)

(6)

(3)

(9)

(4)

(1)


FLOAT VALVE

Check the float valve and its seat (1) for wear or contamination.

Check the valve seat (2) for clogs.

Before installation, check for wear or a weak float valve spring (3).

Check the operation of the float valve.

(1)

(2)

FUEL SYSTEM

(3)

OK CLEAN REPLACE

PILOT SCREW REPLACEMENT

Only remove the pilot screw (1) and limiter cap (2) when necessary for repair or to clean stubborn deposits from the pilot circuit passages.

Removal of the limiter cap requires breaking the pilot screw. A new pilot screw and limiter cap must be installed.

Tampering is a violation of Federal and California law.

When the limiter cap has been broken off, remove the broken pilot screw.

Place the spring on the replacement pilot screw, and install it on the carburetor.

Turn the pilot screw in until it is lightly seated and then turn the screw out the required number of turns.

Pilot screw opening:

WB20XT2: 2 - 1/8 turns out

WB30XT2

:%;7:

1 - 7/8 turns out

Refer to the table above for carburetor pilot screw initial opening setting.

Apply Hondalock 3, LOCTITE® 638, or equivalent to the inside of the limiter cap and then install the cap so the stop prevents the pilot screw from being turned counterclockwise.

Be careful to avoid turning the pilot screw while installing the limiter cap. The pilot screw must stay at its required setting.

(2)

(2)

Pilot screw will break at narrow point.

STOP

(1)

(1)

6-9

FUEL SYSTEM

CHOKE REPLACEMENT


Pull out the choke valve plate (1).

Remove the choke shaft (2) and install a new choke shaft.

Insert a new choke valve plate into the slit (3) of the choke shaft.

Be sure the choke shaft is in the position between the projections (4) of the choke valve plate.

(2)


(3)

(1)

(2)

(4)

(1)

CARBURETOR STUD BOLT

REPLACEMENT


Thread two nuts onto the carburetor stud bolt (1) and tighten them together, and then use a wrench to turn the stud bolt out.

Install and tighten new stud bolts until they are fully seated.

(1)

6-10

dummytext

7. GOVERNOR SYSTEM

GOVERNOR ARM/CONTROL BASE


CONTROL BASE

DISASSEMBLY/ASSEMBLY ························7-3

GOVERNOR ADJUSTMENT ························ 7-4

GOVERNOR

DISASSEMBLY/ASSEMBLY ························ 7-5

MAXIMUM SPEED ADJUSTMENT ·············· 7-6

7

7-1

GOVERNOR SYSTEM

GOVERNOR SYSTEM

GOVERNOR ARM/CONTROL BASE



– Air cleaner (page 6-5)

– Fuel tank (page 6-3)

After installation, adjust the following:

– Governor (page 7-4)

– Idle speed (page 3-6)

– Maximum speed (page 7-6)

GOVERNOR SPRING

INSTALLATION:

Hook the governor spring to the appropriate hole on the control lever as shown.

GOVERNOR ARM BOLT

WB30XT2 WB20XT2

BOLT

WB20XT2: (6 x 20 mm)

WB30XT2: (6 x 12 mm)

BOLT (6 x 12 mm)

CONTROL BASE


NUT (6 mm)

INSTALLATION:

Tighten the nut and then make sure that the clearance is normal as shown.

More than 0.5 mm (0.02 in)

GOVERNOR ARM

GOVERNOR ROD/

THROTTLE RETURN SPRING


Pull the carburetor to a point where the groove (1) of the throttle arm lines up with the governor rod (2) and then lift the governor rod out of the hole of the throttle arm and unhook the throttle return spring (3).

(2)

(1)

(3)

7-2


CONTROL BASE

DISASSEMBLY/ASSEMBLY

Remove the control base Assy (page 7-2).

LOCK NUT (6 mm)

INSTALLATION:

After installation the control base Assy., measure force at 10 mm (0.4 in) from the tip of the control lever (1) by pulling.

Adjust by turning the lock nut (2) so that the gauge shows 19.6 ± 4.9 N (2.0 ±

0.5 kgf) when the control lever starts to move.

(2)

10 mm

(0.4 in)

(1)

CLAW

GOVERNOR SYSTEM

CONTROL LEVER WASHER

INSTALLATION:

Install the control lever washer by aligning the cutout of the control lever washer with the claw of the control base.

LEVER SPRING

INSTALLATION:

Note the installation direction.

CONTROL ADJUST SPRING

CONTROL LEVER

CONTROL LEVER SPACER

SCREW (5 x 25 mm)

CONTROL BASE

(Control lever sliding surface)

7-3

GOVERNOR SYSTEM

GOVERNOR ADJUSTMENT

Loosen the nut (6 mm) (1) of the governor arm.

Turn the governor arm (2) clockwise 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.

Make sure the carburetor throttle valve is fully open.

Tighten the nut and then make sure that the clearance is normal.

(2)


(3)

(4) (1)

7-4


GOVERNOR


Remove the crankshaft (page 13-4).

GOVERNOR WEIGHT (2)

CHECK:

After installing the governor weights, check to be sure they move freely.

GOVERNOR WEIGHT PIN (2)

GOVERNOR WEIGHT HOLDER

(Gear and sliding surface)

GOVERNOR HOLDER CLIP

INSTALLATION:

Install firmly into the groove of the governor holder shaft.

GOVERNOR SYSTEM

WASHER (6 mm)

GROOVE

LOCK PIN

INSTALLATION:

Install firmly into the groove of the governor arm shaft.

GOVERNOR HOLDER SHAFT

(Journal)

WASHER (6 mm)

WASHER (6 mm)

(WB20XT2 only)

GOVERNOR ARM SHAFT

(Journal)

GOVERNOR SLIDER

INSTALLATION:

Spread the governor weights to install the governor slider.

CHECK:

After installing the governor slider, check to be sure it moves smoothly.

GROOVE

7-5

GOVERNOR SYSTEM

MAXIMUM SPEED ADJUSTMENT

Use a tachometer with graduations of 50 min changes.

-1 smaller that will accurately indicate 50 min

(rpm) or

-1 (rpm)

Start the engine and allow it to warm up to normal operating temperature.

Move the control lever (1) to run the engine at the specified maximum speed, and hold the control lever.

Make sure the carburetor throttle valve (2) is fully open.

Turn the screw (3) of the control base to obtain the specified maximum speed.

MAXIMUM SPEED: 3,900 ± 100 min

-1

(rpm)

(3)


(1)

(2)

7-6

dummytext

8. IGNITION SYSTEM

SYSTEM DIAGRAM ······································8-2

IGNITION SYSTEM

TROUBLESHOOTING···································8-2

IGNITION COIL


COOLING FAN/FLYWHEEL


OIL LEVEL SWITCH




OIL ALERT UNIT

REMOVAL/INSTALLATION ························· 8-7

IGNITION COIL AIR GAP

CHECK/ADJUSTMENT ································ 8-7

SPARK TEST ················································ 8-8

SPARK PLUG CAP INSPECTION················ 8-8

IGNITION COIL INSPECTION ······················ 8-9

OIL LEVEL SWITCH INSPECTION ·············· 8-9

ENGINE STOP SWITCH INSPECTION ······ 8-10

OIL ALERT UNIT INSPECTION ················· 8-10

8

8-1

IGNITION SYSTEM

IGNITION SYSTEM

SYSTEM DIAGRAM


Bl

SPARK PLUG IGNITION COIL

ENGINE STOP SWITCH

IG E

OFF

ON

ENGINE STOP SWITCH OIL ALERT UNIT OIL LEVEL SWITCH

Bl

Y

Bu

G

R

W

Black

Yellow

Blue

Green

Red

White

Br Brown

O

Lb

Orange

Light blue

Lg Light green

P

Gr

Pink

Gray

IGNITION SYSTEM TROUBLESHOOTING

NO OR WEAK SPARK AT SPARK PLUG

Check the following before troubleshooting:

– Loose connectors

– Spark plug (page 3-5)

– Engine oil level (page 3-3)

Check the oil level switch (page 8-9)/Oil Alert unit

(page 8-10).

Abnormal

Replace the oil level switch (page 8-6).

Replace the Oil Alert unit (page 8-7).

Normal

Check for continuity between the engine wire harness connectors.

Abnormal


Normal

Check the engine stop switch (page 8-10).

Abnormal

Replace the engine stop switch (page 8-6).

Normal

Check the ignition coil (page 8-9).

Abnormal

Replace the ignition coil (page 8-3).

Normal

Check the spark plug cap (page 8-8).

If necessary, replace the spark plug cap.

8-2


IGNITION COIL



– Fan cover (page 5-2)

– Carburetor (page 6-6)

When installing, route the engine wire harness and

high-tension cord properly (page 2-8).

After installation, check the ignition coil air gap (page 8-7).

ENGINE WIRE HARNESS

IGNITION SYSTEM

BOLT (6 x 25 mm) (2)

SPARK PLUG CAP

HIGH-TENSION CORD

IGNITION COIL CONNECTOR

IGNITION COIL

8-3

IGNITION SYSTEM

COOLING FAN/FLYWHEEL


REMOVAL

Remove the ignition coil (page 8-3).

WOODRUFF KEY

MAGNET PART


GROMMET

(WB20XT2 only)

SIDE PLATE

BOLT (6 × 22 mm)

STARTER PULLEY

COOLING FAN

FLYWHEEL

REMOVAL:

Use the commercially available tool (1) to remove the flywheel.

(1)

TWO-JAW PULLER

OTC1035

NUT (14 mm)

(Threads and seating surface)

75 N·m (7.6 kgf·m, 55 lbf·ft)

REMOVAL:

Hold the flywheel (1) with a commercially available strap wrench (2), being careful not to damage the magnet part.

Remove the flywheel nut (14 mm) (3).

(2)

(1)

(3)

8-4


INSTALLATION

• Clean the tapered parts (1) of dirt, oil, grease, and other foreign material before installation.

• Be sure there are no metal parts or other foreign material on the magnet part (2) of the flywheel.

Set the woodruff key (3) in the key groove (4) of the crankshaft securely.

Set the flywheel (5) by aligning the key slot (6) with the woodruff key on the crankshaft.

(4)

IGNITION SYSTEM

(3) (2) (6)

Attach the cooling fan (1) to the flywheel (2) by aligning the four projections of the cooling fan with the holes of the flywheel.

Attach the starter pulley (3) by aligning the following:

– Holes of the pulley and tabs of the cooling fan

– Tab of the pulley and hole of the flywheel

Align

(1)

(1) Align

(5)

(3)

Apply a light coat of oil to the threads and the seating surface of the nut (1) and loosely tighten the nut.


Tighten the flywheel nut to the specified torque.


(2)

(3)

Align

(2)

(1)

8-5

IGNITION SYSTEM

OIL LEVEL SWITCH


Disconnect the Oil Alert unit connector.

Remove the camshaft (page 13-4).

Take care not to drop the valve lifter.


OIL LEVEL SWITCH

O-RING

NUT (10 mm)

10 N·m (1.0 kgf·m, 7 lbf·ft)



Remove the engine stop switch only if necessary for engine stop switch or fan cover replacement.

Remove the fan cover (page 5-2).

Straighten the tab (1) of the engine stop switch (2) and remove the engine stop switch.

Install the engine stop switch to the fan cover, aligning its groove with the boss of the fan cover.

Bend the tab until it is fully seated on the fan cover so the engine stop switch is held.

The tab is used for ground terminal.

Install the fan cover (page 5-2).

8-6

BOLT (6 x 12 mm) (2)

Align

(1) (2)


OIL ALERT UNIT


Disconnect the Oil Alert unit connectors (1).

Remove the 6 x 12 mm bolt (2) and Oil Alert unit (3).

Install the Oil Alert unit and bolt.

Hold the Oil Alert unit against the boss (4) of the stay, and then tighten the bolt.

(4)

Route the wire harness properly (page 2-10).

IGNITION SYSTEM

(2)

(3)

IGNITION COIL AIR GAP

CHECK/ADJUSTMENT


Insert the thickness gauge (1) of proper thickness between the ignition coil (2) and the flywheel (3).

IGNITION COIL AIR GAP:

0.2 – 0.6 mm (0.01 – 0.02 in)

(2)

• Avoid the magnet part of the flywheel when adjusting.

• Adjust the ignition coil air gap equally on both sides.

If measured clearance is out of specification, adjust the air gap.

Loosen the two 6 x 25 mm bolts (4).

Insert the thickness gauge of proper thickness between the ignition coil and flywheel.

Push the ignition coil firmly against the flywheel and tighten the ignition coil bolts securely.

Remove the thickness gauge.

(3)

0.2 – 0.6 mm (0.01 – 0.02 in)

(1)

0.2 – 0.6 mm

(0.01 – 0.02 in)

(1)

(4)

8-7

IGNITION SYSTEM

SPARK TEST

(2)

Never hold the high-tension cord with wet hands while performing this test.

Check for the following before conducting the spark test.

• Faulty spark plug

• Loose spark plug cap

• Water in the spark plug cap (leaking the ignition coil secondary voltage)

• Loose ignition coil connector

Disconnect the spark plug cap (1) from the spark plug

(2).

Connect a known-good spark plug (3) to the spark plug cap and ground the spark plug to the cylinder head cover bolt (4).

Turn the engine stop switch to "ON" position.

Crank the engine by pulling the recoil starter and check whether sparks jump across the electrodes.

SPARK PLUG CAP INSPECTION

Measure the resistance of the spark plug cap by attaching one ohmmeter probe to the terminal in the spark plug cap and the other to the high-tension cord terminal.

RESISTANCE: 7.5 – 12.5 k Ω (20°C/68°F)

If measured resistance is out of specification, replace

the spark plug cap (page 8-3).

(4)

(3)

(1)


8-8


IGNITION COIL INSPECTION


PRIMARY SIDE

Disconnect the ignition coil connector (1).

Measure the resistance of the primary coil by attaching one ohmmeter probe to the ignition coil wire terminal (2) and the other at the iron core (3).

RESISTANCE: 0.6 – 0.9

Ω


the ignition coil (page 8-3).

(1)

SECONDARY SIDE

Disconnect the spark plug cap from the high-tension cord (1).

Measure the resistance of the secondary coil by attaching one ohmmeter probe to the high-tension cord and the other at the iron core (2).

RESISTANCE: 5.6 – 6.9 k

Ω


the ignition coil (page 8-3).

(1)

OIL LEVEL SWITCH INSPECTION

Check the oil level (page 3-3).

Disconnect the Oil Alert unit connector (1).

Check the continuity between the oil level switch connector and engine ground.

There should be no continuity when the engine is full of oil.

Drain the engine oil completely (page 3-3).

Check the continuity between the oil level switch connector and engine ground.

There should be continuity.

Check the continuity between the oil level switch connector and engine ground while filling the engine with oil.

The ohmmeter reading should go from continuity to no continuity as the oil is filled.

If the correct continuity is not obtained, replace the oil

level switch (page 8-6).

(2)

IGNITION SYSTEM

(3)

(2)

(1)

8-9

IGNITION SYSTEM

ENGINE STOP SWITCH INSPECTION

Remove the engine stop switch connector (1) from the engine wire harness.

Check the continuity between the terminals at each switch position.

Switch position

ON

OFF

Continuity

No

Yes

If the correct continuity is not obtained, replace the

engine stop switch (page 8-6).

OIL ALERT UNIT INSPECTION

Remove the Oil Alert

unit (page 8-7).

Check the continuity between the terminals, and Oil

Alert unit body.

Unit: k Ω

(–)

Bl (1)

Y (2)

Body (3)

Bl (1)

–

0.5 – 10

(+)

Y (2)

0.5 – 10

–

Body (3)

–

(1)


(1)

(2) (3)

8-10

dummytext

9. STARTING SYSTEM

RECOIL STARTER


RECOIL STARTER

DISASSEMBLY/ASSEMBLY ························ 9-3

RECOIL STARTER INSPECTION ················ 9-6

9

9-1

STARTING SYSTEM

STARTING SYSTEM

RECOIL STARTER



BOLT (6 x 10 mm) (3)

9-2

RECOIL STARTER


RECOIL STARTER


STARTING SYSTEM

• Wear gloves and eye protection.

• During disassembly/assembly, take care not to allow the return spring to come out.

DISASSEMBLY

Remove the recoil starter (page 9-2).

SPRING RETAINER

(Inside)

RECOIL STARTER CENTER SCREW

5.4 N·m (0.6 kgf·m, 4.0 lbf·ft)

(Threads)

FRICTION PLATE

FRICTION SPRING

RATCHET (2)

(Sliding surface)

RATCHET SPRING (2)

RECOIL STARTER PULLEY

REINFORCEMENT GRIP

STARTER RETURN SPRING

STARTER GRIP

RECOIL STARTER CASE

(Pulley sliding surface)

9-3

STARTING SYSTEM

ASSEMBLY

Pass the recoil starter rope (1) through the hole (2) of the recoil starter pulley (3), and then tie the rope as shown.

Wind the recoil starter rope onto the recoil starter pulley counterclockwise as shown.

(2)


Hook the outer hook (1) of the starter return spring (2) to the groove (3) of the recoil starter pulley (4), and then install the starter return spring by winding it.

(3)

(2) (3)

(1)

(1)

Apply grease to the starter pulley sliding surface (1) of the recoil starter case (2).

Set the recoil starter pulley (3) to the recoil starter case by aligning the inner hook (4) of the starter return spring with the boss (5) of the recoil starter case as shown.

(1)

(3)

(4)

(4)

Apply grease to the ratchets (1).

Install the ratchet springs (2) and ratchets to the recoil starter pulley (3) as shown.

(2)

(1) (1)

(5)

(2)

(2) (3)

9-4


Apply grease to the inside of the spring retainer (1).

Apply locking agent (Hondalock 1 or equivalent) to the threads of the center screw (2).

Set the friction spring (3), friction plate (4), and spring retainer to the recoil starter pulley in the direction as shown.

Hold the spring retainer and tighten the center screw to the specified torque.

TORQUE: 5.4 N·m (0.6 kgf·m, 4.0 lbf·ft)

Turn the recoil starter pulley (1) 2 turns counterclockwise to preload the starter return spring.

Be sure to hold the recoil starter pulley.

(2)

STARTING SYSTEM

(1)

(4)

(3)

(1)

Pass the recoil starter rope (1) through hole (2) of the recoil starter case, starter grip (3), and reinforcement grip (4), and then tie the rope as shown. Be sure to hold the recoil starter pulley (5).

Check the recoil starter operation (page 9-6).

(5) (2) (4)

(3) (1)

9-5

STARTING SYSTEM

RECOIL STARTER INSPECTION

RECOIL STARTER OPERATION

Remove the recoil starter Assy. (page 9-2).

Pull the starter grip (1) several times to inspect that the ratchets (2) are operated properly (the ratchet ends come out from the spring retainer (3)).

(2)


(1)

STARTER PULLEY

Remove the recoil starter Assy. (page 9-2).

Inspect the square holes (1) of the starter pulley (2) for deformation.

(2)

(3)

(1)

9-6

dummytext

10. PUMP

TOOLS·························································10-2

INLET PIPE/OUTLET PIPE

REMOVAL/INSTALLATION························10-3

PUMP CASE/IMPELLER COVER


IMPELLER/END PLATE

REMOVAL/INSTALLATION ······················· 10-7

MECHANICAL SEAL REPLACEMENT······ 10-8

WATER PUMP VACUUM TESTER ············ 10-9

10

10-1

PUMP

TOOLS

PUMP


07746-0010100

Driver

07749-0010000


Mechanical seal attachment

07948-9540000

Water pump vacuum tester

07APJ-YB3A100

30

20

0.8

0.6

1

0.4

0.2

0

" Hg

10-2




WB20XT2

HOSE COUPLING PACKING

(Commercially available)

OUTLET PIPE

FILLER CAP

HOSE COUPLING


SEAL RING

BOLT (8 x 25 mm) (4)

PUMP

OUTLET

PACKING

INLET VALVE

INSTALLATION:

Check the inlet valve for breakage or damage.

Align the tab (1) on the inlet valve with the groove (2) of the inlet pipe.

(1)

ALIGN

(2)

HOSE BAND

HOSE CLAMP RING




HOSE CLAMP RING


HOSE BAND (2)

INLET PIPE

BOLT (8 x 25 mm) (3)

HOSE COUPLING


SUCTION HOSE


STRAINER

10-3

PUMP

WB30XT2



OUTLET PIPE

HOSE COUPLING



FILLER CAP

SEAL RING

BOLT (10 x 32 mm) (4)

OUTLET

PACKING

INLET VALVE

INSTALLATION:

Check the inlet valve for breakage or damage.

Align the tab (1) on the inlet valve with the groove (2) of the inlet pipe.

(1)

ALIGN (2)

HOSE BAND

HOSE CLAMP RING




HOSE CLAMP RING


HOSE BAND (2)

INLET PIPE

BOLT (10 x 32 mm) (4)

HOSE COUPLING


SUCTION HOSE


STRAINER

10-4

PUMP



WB30XT3


INSTALLATION:

Install the hose coupling packing [1] in the groove [2] of the hose clamp ring.

[1]

FILLER CAP

[2]

OUTLET PIPE

HOSE COUPLING (2)

SEAL RING

BOLT (10 x 32 mm) (4)

OUTLET

PACKING

INLET VALVE

INSTALLATION:

Check the inlet valve for breakage or damage. Align the tab [1] on the inlet valve with the groove [2] of the inlet pipe.

[1]

ALIGN [2]

HOSE CLAMP RING (2)

HOSE BAND (3)

INLET PIPE

BOLT (10 x 32 mm) (4)


INSTALLATION:

Install the hose coupling packing

[1] in the groove

[2] of the hose clamp ring.

[1]

[2]

SUCTION HOSE


STRAINER

10-2




WB20XT2

Remove the engine (page 11-2).

PUMP

STUD BOLT (6 x 50 mm) (2)

SHORT

VOLUTE CASE

INSTALLATION:

Check the mating surface for damage and nicks.

LONG

CAP NUT (6 mm) (3)

STUD BOLT (6 x 63.5 mm)

O-RING (49 x 5.7 mm)

O-RING (217.5 x 3.5 mm)


CASING

BOLT (8 x 28 mm) (4)

SEAL RING

DRAIN CAP

10-5

PUMP

WB30XT2



STUD BOLT (3)

VOLUTE CASE

INSTALLATION:


CAP NUT (6 mm) (3)


CASING SEAL RING


CASING

BOLT (10 x 32 mm) (4)

SEAL RING

DRAIN CAP

10-6



WB20XT3


SHORT

STUD BOLT (3)

LONG

VOLUTE CASE

INSTALLATION:


CAP NUT (6 mm) (3)

SEAL RING


O-RING (217.5 x 3.5 mm)

CASING

BOLT (8 x 28 mm) (4)

DRAIN CAP

10-3

10-4

WB30XT3


STUD BOLT (3)

SHORT

LONG

VOLUTE CASE

INSTALLATION:


CAP NUT (6 mm) (3)

SEAL RING


CASING SEAL RING

CASING

BOLT (10 x 32 mm) (4)

DRAIN CAP


IMPELLER/END PLATE REMOVAL/INSTALLATION

Remove the casing (page 10-5).

WB20XT2: CASING COVER

SEALING WASHER (4)

PUMP

BOLT

WB20XT2: (8 x 28 mm) (4)

WB30XT2: (10 x 32 mm) (4)

RUBBER RING

ADJUSTER SHIM


FLOATING SEAT

INSTALLATION:

Check the seat surface for damage, nicks.

Apply soapy water to the rubber ring and install the floating seat in the rubber ring.

Push the rubber ring and the floating seat into the impeller by finger pressure.

After installing, check to be sure the seat and rubber ring are fully seated and are not tilted.

IMPELLER

REMOVAL:

Hold the flywheel (1) with a commercially available strap wrench (2), being careful not to damage the magnet (3) part.

Remove the impeller.

(2)

INSTALLATION:


Tighten the impeller to the specified torque.

25 N·m (2.5 kgf·m, 18 lbf·ft)

After installation, check the impeller clearance:

NOTE1:

(2)

(3)

(1) (1)

NOTE 1 IMPELLER CLEARANCE CHECK

(3)

page 3-11

10-7

IMPELLER/END PLATE REMOVAL/INSTALLATION

Remove the casing ( page 10-3 ).


SEALING WASHER (4)

BOLT (8 x 28 mm) (4)

RUBBER RING

ADJUSTER SHIM


FLOATING SEAT

INSTALLATION:

Check the seat surface for damage, nicks.

Apply soapy water to the rubber ring and install the floating seat in the rubber ring.

Push the rubber ring and the floating seat into the impeller by finger pressure.

After installing, check to be sure the seat and rubber ring are fully seated and are not tilted.

IMPELLER

REMOVAL:

Hold the flywheel [1] with a commercially available strap wrench [2], being careful not to damage the magnet part [3].

Remove the impeller.

[2]

INSTALLATION:

Hold the flywheel [1] with a commercially available strap wrench [2], being careful not to damage the magnet part [3].

Tighten the impeller to the specified torque.

25 N·m (2.5 kgf·m, 18 lbf·ft)

(

After installation, check the impeller clearance

page 3-2 ).

[2]

[3]

[1] [1]

[3]

10-5

PUMP

MECHANICAL SEAL REPLACEMENT

Drive out the mechanical seal (1) from the inside using the special tools.

TOOLS:

Driver (2)

Attachment, 32 x 35 mm

07749-0010000

07746-0010100

(1)


(2)

(3)

Apply liquid sealant (Hondabond HT or equivalent) to the outside surface of a new mechanical seal (1).

Drive the mechanical seal until it is fully seated on the end using the special tools.

TOOLS:

Driver (2) 07749-0010000

Mechanical seal attachment (3) 07948-9540000

After installing, check to be sure the seal is fully seated and is not tilted in the casing cover.

(1)

(2)

(3)

10-8


WATER PUMP VACUUM TEST

Use the water pump vacuum tester to confirm the pump develops the proper suction vacuum, ensuring it will prime and operate properly.

TOOLS:

Water Pump Vacuum Tester 07APJ-YB3A100

Install thread tape or sealant to the vacuum gauge and install in the base plate.

20

30

0.8

1

0.6

0.4

0

0.2

" Hg

PUMP

Fill the pump housing with water.

Position a garden hose in the discharge port and 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.

Start the engine, position the throttle lever in the fast position, and allow the engine to warm up for several minutes.

Adjust the maximum engine rpm to the proper no-load specification.

Position the vacuum tester against the suction port to obtain the vacuum reading.

Minimum Vacuum:

22 inches of mercury (in. Hg) at sea level

Vacuum reading will decrease by approximately

1 in. Hg per 1000 ft increase in elevation.

Shut off the engine and confirm the vacuum gauge reading remains steady. This verifies the intake flapper is sealing.

100 x Kpa "Hg

BAR

0.2

1

30

0.4

0.6

0.8

25

15

VACUUM TEST RESULTS

If the vacuum gauge won't remain steady after shutting off the engine, disassemble and inspect the flapper for wear or damage.

A vacuum reading below 22 inches of mercury (at sea level) indicates a problem with the pump. If the vacuum is low, disassemble the pump and inspect the:

• Impeller and volute for damage or wear. Check the impeller/volute clearance.

• Mechanical seal for damage.

• Pump case housing and O-rings for damage or leaks.

MAINTENANCE

If the customer complains that the pump won't prime, but the vacuum reading is good, the customer likely has an air leak in the suction hose or fittings, or the suction head is too high.

If the vacuum gauge needle does not return to zero, pull out the spigot on the top of the gauge to allow the gauge to vent, and then press the spigot back in.

The gauge is filled with glycerin. If the fluid level gets low, remove the top plug and add glycerin, available from many local hydraulic supply houses. Glycerin is available in 1-pint bottles, part number 3910K816, from

McMaster Carr Supply Company, telephone 330-995-5500.

10-9

MEMO

dummytext

11. ENGINE REMOVAL/INSTALLATION

ENGINE REMOVAL/INSTALLATION ·········11-2

11

11-1




WB20XT2


NUT (8 mm) (4) FRAME

NUT (8 mm) (4)

11-2

ENGINE MOUNT RUBBER (4)

INSTALLATION:

Check for cracking, deformation, or other damage before installation.

Install by aligning with the hole in the frame.


WB30XT2


FRAME

NUT (8 mm) (4)

ENGINE MOUNT RUBBER (4)

(Rubber mount type)

INSTALLATION:

Check for cracking, deformation, or other damage before installation.

Install by aligning with the hole in the frame as shown.

Do not use Do not use

NUT (8 mm) (4)

11-3

MEMO

dummytext

12. CYLINDER HEAD

TOOLS·························································12-2

CYLINDER HEAD


CYLINDER HEAD

DISASSEMBLY/ASSEMBLY ······················12-4

CYLINDER HEAD/VALVES

INSPECTION ··············································· 12-5

VALVE GUIDE REPLACEMENT ················ 12-8

VALVE GUIDE REAMING ·························· 12-9

VALVE SEAT RECONDITIONING············ 12-10

12

12-1

CYLINDER HEAD

CYLINDER HEAD

TOOLS

Valve guide driver, 5.5 mm

07742-0010100

Valve guide reamer, 5.510 mm

07984-2000001


12-2


CYLINDER HEAD


Set the piston at top dead center of the cylinder compression stroke (page 3-7).


– Fan cover (page 5-2)

– Carburetor (page 6-6)

– Control base Assy (page 7-2)

– Muffler (page 14-2)

After installation, inspect following:

– Valve clearance (page 3-7)

– Cylinder compression (page 12-5)

CYLINDER HEAD COVER PACKING

BOLT (Threads and seating surface)

WB20XT2: (8 x 55 mm) (4)

WB30XT2: (8 x 60 mm) (4)

24 N·m (2.4 kgf·m, 18 lbf·ft)


Loosen and tighten the bolts in a crisscross pattern in 2 – 3 steps.

CYLINDER HEAD COVER

CYLINDER HEAD

PUSH ROD (2)

BOLT (6 x 12 mm) (4)

BOLT (6 x 12 mm) (2)

SHROUD

CYLINDER HEAD

CYLINDER HEAD GASKET

DOWEL PIN (2)

12-3

CYLINDER HEAD

CYLINDER HEAD


Remove the cylinder head (page 12-3).


INTAKE/EXHAUST VALVE SPRING RETAINER

REMOVAL:

Push down and slide the valve spring retainer (1) to the side so that the valve stem (2) slips through the hole at the side of the valve spring retainer.

Do not remove the valve spring retainer while the cylinder head is installed to the cylinder barrel, or the valve will drop into the cylinder.

(1)

VALVE GUIDE CLIP

(2)

(Sliding surface and stem end)

EXHAUST VALVE

INSTALLATION:

Do not interchange with the intake valve.

The exhaust valve is smaller than the intake valve.

EXHAUST VALVE GUIDE

INTAKE VALVE GUIDE

SPARK PLUG

18 N·m (1.8 kgf·m, 13 lbf·ft)

CYLINDER HEAD

VALVE SPRING (2)

VALVE STEM SEAL

(Sliding surface and stem end)

INTAKE VALVE

INSTALLATION:

Do not interchange with the exhaust valve.

The intake valve is larger than the exhaust valve.

PUSH ROD GUIDE PLATE

ROCKER ARM PIVOT BOLT (2)

24 N·m (2.4 kgf·m, 18 lbf·ft)

LOCK NUT (2)

10 N·m (1.0 kgf·m, 7 lbf·ft)

(Threads and pivot)

ROCKER ARM PIVOT (2)

VALVE ROCKER ARM (2) (Tappet surface and pivot)

INSTALLATION:

Before installing the rocker arm, check for wear on the surfaces of the rocker arm that contact the pivot bolt, push rod, and valve stem.

12-4


CYLINDER HEAD/VALVES

INSPECTION

CYLINDER COMPRESSION CHECK

Start the engine and warm up to normal operating temperature.

Turn off the engine stop switch to stop the engine.

Turn the fuel valve lever to the OFF position, and then loosen the drain screw of the carburetor to drain the fuel

completely (page 6-3).

Remove the spark plug (page 3-5).

Pull the recoil starter several times to expel unburned gas.

Attach a commercially available compression gauge (1) to the spark plug hole.

Pull the recoil starter forcefully to measure stable cylinder compression.

CYLINDER

COMPRESSION:

0.49 - 0.69 MPa

(5.0 - 7.0 kgf/cm

2

, 71 - 100 psi)/

600 min

-1

(rpm)

(1)

CYLINDER HEAD WARPAGE

Check the spark plug hole and valve areas for cracks.

Clean any gasket material from the cylinder head mating surface and check the cylinder head warpage using a straightedge (1) and thickness gauge (2).

(2)

Be careful not the damage the mating surface.

SERVICE LIMIT: 0.10 mm (0.004 in)

If the measurement is more than the service limit,

replace the cylinder head (page 12-3).

CYLINDER HEAD

(1)

12-5

CYLINDER HEAD

VALVE SEAT WIDTH

Remove the carbon deposits from the combustion

chamber (page 3-9).

Inspect each valve face for irregularities.

If necessary, replace the valve.

Apply a light coat of Prussian Blue or erasable felttipped marker ink to each valve seat.

Insert the valve, and snap it closed against its seat several times. Be sure the valve does not rotate on the seat.

The transferred marking compound will show any area of the valve face that is not concentric.

Measure the valve seat width of the cylinder head.

WB20XT2:

STANDARD:

IN/EX: 0.70 – 0.90 mm (0.028 – 0.035 in)

SERVICE LIMIT:

IN/EX: 2.0 mm (0.08 in)

WB30XT2:

STANDARD:

IN: 0.70 – 0.90 mm (0.028 – 0.035 in)

EX: 0.90 – 1.10 mm (0.035 – 0.043 in)

SERVICE LIMIT:

IN/EX: 2.0 mm (0.08 in)


recondition the valve seat (page 12-10).

Check whether the valve seat contact area of the valve is too high.

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 to remove any carbon deposits before measuring the guide I.D. (1).

TOOL:

Valve guide reamer 5.510 mm (2) 07984-2000001

(2)

TOO LOW

TOO HIGH


VALVE LAPPER


VALVE SEAT

WIDTH

HANDLE


• Turn the valve guide reamer (special tool) clockwise, never counterclockwise.

• Continue to rotate the special tool while removing it from the valve guide.

(1)

12-6


Measure and record each valve guide I.D.

STANDARD: 5.500 – 5.512 mm (0.2165 – 0.2170 in)


If the measured valve guide I.D. is more than the

service limit, replace the valve guide (page 12-8).

VALVE FACE/VALVE STEM O.D.

Inspect each valve face (1) for irregularities.

If necessary, replace the valve.

Inspect each valve (2) for bending or abnormal stem wear.

If necessary, replace the valve (page 12-4).

Measure and record each valve stem O.D.

STANDARD:

IN: 5.468 – 5.480 mm (0.2153 – 0.2157 in)

EX: 5.425 – 5.440 mm (0.2136 – 0.2142 in)

SERVICE LIMIT:

IN: 5.318 mm (0.2094 in)

EX: 5.275 mm (0.2077 in)

If the measurement is less than the service limit,

replace the valve (page 12-4).

(1)

GUIDE-TO-STEM CLEARANCE

Subtract each valve stem O.D. from the corresponding guide I.D. to obtain the guide-to-stem clearance.

STANDARD:

IN: 0.020 – 0.044 mm (0.0008 – 0.0017 in)

EX: 0.060 – 0.087 mm (0.0024 – 0.0034 in)

SERVICE LIMIT:

IN: 0.10 mm (0.004 in)

EX: 0.12 mm (0.005 in)

If the calculated clearance is more than the service limit,

replace the valve and valve guide as a set (page 12-8).

CYLINDER HEAD

(2)

12-7

CYLINDER HEAD

VALVE SPRING FREE LENGTH/

PERPENDICULARITY

Measure the valve spring free length.

STANDARD: 30.5 mm (1.20 in)


If the measured length is less than the service limit,

replace the valve spring (page 12-4).

Measure the valve spring perpendicularity.

SERVICE LIMIT: 1.5° max.

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.

If necessary, replace the push rod (page 12-3).


VALVE GUIDE REPLACEMENT

Chill the replacement valve guides in the freezer section of a refrigerator for about an hour.

Use a hot plate or oven to heat the cylinder head evenly to 150°C (302°F).

To avoid burns, use heavy gloves when handling the heated cylinder head.

• Do not use a torch to heat the cylinder head; warpage of the cylinder head may result.

• Do not get the cylinder head hotter than 150°C

(302°F); excessive heat may loosen the valve seat.

12-8


Remove the heated cylinder head from the hot plate and support it with wooden blocks.

Drive the valve guides (1) out of the cylinder head from the combustion chamber side.

TOOL:

Valve guide driver 5.5 mm (2) 07742-0010100

When driving the valve guides out, be careful not to damage the cylinder head.

Remove the new valve guides (1) from the refrigerator one at a time as needed.

Install the valve guides from the valve spring side of the cylinder head.

TOOL:

Valve guide driver 5.5 mm (2) 07742-0010100

Drive the exhaust valve guide until new valve guide clip

(3) is fully seated as shown.

Drive the intake valve guide to the specified height

(measured from the end of the valve guide to the cylinder head as shown).

IN VALVE INSTALLATION HEIGHT:

4.8 – 5.2 mm (0.19 – 0.20 in)

After installing the valve guide, check the guide for damage.

Replace the valve guide if damaged.

Let the cylinder head cool to room temperature.

Ream the valve guide (page 12-9).

IN:

VALVE GUIDE REAMING

For best results, be sure the cylinder head is at room temperature before reaming valve guides.

Coat the reamer and valve guide with cutting oil.

TOOL:

Valve guide reamer 5.510 mm (1) 07984-2000001

Rotate the reamer clockwise through the valve guide the full length of the reamer.

(2)

COMBUSTION

CHAMBER SIDE

• Turn the special tool (valve guide reamer) clockwise, never counterclockwise.

• Continue to rotate the special tool while removing it from the valve guide.

Thoroughly clean the cylinder head to remove any cutting residue.

VALVE SPRING SIDE

CYLINDER HEAD

(2)

EX:

(3)

(1)

(1)

HANDLE


(1)

12-9

CYLINDER HEAD

Check the valve guide bore; it should be straight, round, and centered in the valve guide. Insert the valve and check operation. If the valve does not operate smoothly, the guide may have been bent during installation.

Replace the valve guide if it is bent or damaged (page

12-8).

Check the valve guide-to-stem clearance (page 12-7).

VALVE SEAT RECONDITIONING

Inspect the valve seat contact area (page 12-6).

Using a 45° seat cutter, remove any roughness or irregularities from the seat.

If the contact area is too low on the valve, the seat must be raised using a 60° interior cutter.

If the contact area is too high on the valve, the seat must be lowered using a 31° flat cutter.

Valve seat cutter (1), grinder or equivalent valve seat refacing equipment is recommended to correct a worn valve seat.

• Turn the cutter clockwise, never counterclockwise.

• Continue to turn the cutter as you lift it from the valve seat.

TOOLS (Commercially available):

Valve seat cutter, 31°


NWYCU115

NWYCU122


Solid pilot (short) 5.5 mm

Accessory kit

T-wrench

Adapter, 1/2"-3/8"

MWYCU111

NWYPM10055SH

NWYKACC246

NWYTW505

NWYTW503-1

Make a light pass with the 45° cutter to remove any possible burrs at the edge of the seat.

Be sure that the width of the finished valve seat is within specification.

STANDARD:

WB20XT2:

IN/EX: 0.70 – 0.90 mm (0.028 – 0.035 in)

WB30XT2:

IN: 0.70 – 0.90 mm (0.028 – 0.035 in)

EX: 0.90 – 1.10 mm (0.035 – 0.043 in)

12-10


45°

60°

TOO LOW

31°

TOO HIGH

45°

(1)


Lap the valves into their seats, using a commercially available valve lapper and lapping compound.

After lapping, wash all residual compound off the cylinder head and valve.

• Do not push the valve against the seat with force during lapping. Apply a light pass with the valve lapper.

• Avoid lapping the valve in the same position as it causes uneven wear. Lap the valve by turning the lapper slowly.

• Take care not to allow the lapping compound to enter the gap between the stem and guide.

CYLINDER HEAD

VALVE LAPPER


12-11

MEMO

dummytext

13. CRANKCASE

TOOLS·························································13-2

CRANKCASE COVER


CRANKSHAFT/PISTON


PISTON

DISASSEMBLY/ASSEMBLY ······················ 13-5

CRANKCASE COVER/CYLINDER BARREL/

PISTON/CONNECTING ROD/CRANKSHAFT/

CAMSHAFT INSPECTION·························· 13-6

CRANKSHAFT BEARING/OIL SEAL

REPLACEMENT ······································· 13-13

13

13-1

CRANKCASE

CRANKCASE

TOOLS


07746-0010100


07746-0010200



07746-0010400

Pilot, 25 mm

07746-0040600

Pilot, 22 mm

07746-0041000

Driver

07749-0010000


07946-6920100

13-2


CRANKCASE COVER


Drain the engine oil (page 3-3).

Remove the end plate (page 10-7).

DOWEL PIN (2)

CASE COVER PACKING

CRANKCASE

OIL FILLER CAP

OIL FILLER CAP

(With oil level gauge)

OIL FILLER CAP PACKING (2)

CHECK:


CRANKCASE COVER

INSTALLATION:

Be careful not to damage the oil seal lips.

BOLT

WB20XT2: (6 x 28 mm) (7)

12 N·m (1.2 kgf·m, 9 lbf·ft)

WB30XT2: (8 x 32 mm) (6)

24 N·m (2.4 kgf·m, 18 lbf·ft)

13-3

CRANKCASE

CRANKSHAFT/PISTON



– Fuel tank (page 6-3)

– Flywheel (page 8-4)

– Cylinder head (page 12-3)

– Crankcase cover (page 13-3)

PISTON (Outer surface and big end bearing)

INSTALLATION:

Install the piston Assy. to the cylinder barrel with the mark

(1) on the piston head toward the push rod hole (2) of the cylinder head.

(1)

(2)


VALVE LIFTER

(Pivot, pivot end and slipper surface)

REMOVAL:

Mark the valve lifters so that the intake and exhaust sides can be distinguished.

INSTALLATION:

Attach the valve lifters to the cylinder barrel immediately before installing the camshaft.

CYLINDER BARREL

(Cylinder inner surface)

CONNECTING ROD LOWER

(Big end bearing)

INSTALLATION:

Set the connecting rod lower with the oil dipper toward the camshaft.

13-4

CONNECTING ROD BOLT (2)

(Threads and seating surface)

WB20XT2: (7 x 34 mm)

12 N·m (1.2 kgf·m, 9 lbf·ft)

WB30XT2: (6 x 34.5 mm)

9.8 N·m (1.0 kgf·m, 7.2 lbf·ft)

CAMSHAFT

(Cam journal and profile)

INSTALLATION:

Install the timing gear (1) of the crankshaft and camshaft (2) by aligning the punch marks (3).

(3)

CRANKSHAFT

(Pin and gear teeth)

INSTALLATION:

Be careful not to damage the oil seal lips.

(1)

(2)


PISTON


Remove the piston. (page 13-4).

CRANKCASE

PISTON RING SET (Entire surface)

INSTALLATION:

To install the oil ring, install the spacer (1) first, and then install the side rails (2).

Be sure that the top ring (3) and second ring (4) are not interchanged.

Install the top ring and second ring on the piston with the maker mark side facing up.

Check that the piston rings rotate smoothly after installing them.

Space the piston ring end gaps 120° apart, and do not align the ring end gaps with the piston pin bore.

(3)

(4)

(2)

(1)

(2)

TOP RING

SPACER

120°

120°

10 mm (0.4 in)

120°

10 mm (0.4 in)

MAKER MARK

SIDE RAIL

SECOND RING

SIDE RAIL

OIL RING

(COMBINATION RING)

PISTON PIN

(Outer surface)

MARK

PISTON

PISTON PIN CLIP (2)

INSTALLATION:

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 nose pliers, and rotating the clip in.

Do not align the end gap (1) of the piston pin clip with the cutout (2) of the piston pin bore.

(1)

CONNECTING ROD UPPER

(Small end bearing)

INSTALLATION:

Set the connecting rod upper with the long end toward the mark on the piston head.

LONG END

(2)

13-5

CRANKCASE

CRANKCASE COVER/CYLINDER

BARREL/PISTON/CONNECTING ROD/

CRANKSHAFT/CAMSHAFT

INSPECTION

CAMSHAFT HOLDER I.D.

CRANKCASE COVER SIDE

Measure the camshaft holder I.D. of the crankcase cover.

STANDARD: 14.000 – 14.018 mm (0.5512 – 0.5519 in)



replace the crankcase cover (page 13-3).

Inspect the camshaft O.D. (page 13-12).


CYLINDER BARREL SIDE

Measure the camshaft holder I.D. of the cylinder barrel assembly.

STANDARD: 14.000 – 14.018 mm (0.5512 – 0.5519 in)



replace the cylinder barrel (page 13-4).

Inspect the camshaft O.D. (page 13-12).

CYLINDER SLEEVE I.D.

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.

WB20XT2:

STANDARD: 60.000 – 60.015 mm

(2.3622 – 2.3628 in)


WB30XT2:

STANDARD: 68.000 – 68.015 mm

(2.6772 – 2.6778 in)



replace the cylinder barrel (page 13-4).

Inspect the piston skirt O.D. (page 13-7).

Y

X

TOP

MIDDLE

BOTTOM

13-6


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° to the piston pin bore.

WB20XT2:

STANDARD: 59.965 – 59.985 mm

(2.3608 – 2.3616 in)


WB30XT2:

STANDARD: 67.985 – 67.995 mm

(2.6766 – 2.6770 in)



replace the piston (page 13-5).

Inspect the cylinder sleeve I.D. (page 13-6).

PISTON-TO-CYLINDER CLEARANCE

Subtract the piston skirt O.D. from the cylinder sleeve

I.D. to obtain the piston-to-cylinder clearance.

WB20XT2:

STANDARD: 0.015 – 0.050 mm

(0.0006 – 0.0020 in)


WB30XT2:

STANDARD: 0.005 – 0.030 mm

(0.0002 – 0.0012 in)


If the calculated clearance is more than the service

limit, replace the piston (page 13-5) and recheck the

clearance.

If the clearance is still more than the service limit with

the new piston, replace the cylinder barrel (page 13-4).

PISTON PIN BORE I.D.

Measure and record the piston pin bore I.D. of the piston.

WB20XT2:

STANDARD: 13.002 – 13.008 mm

(0.5119 – 0.5121 in)


WB30XT2:

STANDARD: 18.002 – 18.008 mm

(0.7087 – 0.7090 in)



replace the piston (page 13-5).

Inspect the piston pin O.D. (page 13-8).

90°

CRANKCASE

10 mm

(0.4 in)

13-7

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.

WB20XT2:

STANDARD: 12.994 – 13.000 mm

(0.5116 – 0.5118 in)


WB30XT2:

STANDARD: 17.994 – 18.000 mm

(0.7084 – 0.7087 in)



replace the piston pin (page 13-5).

Inspect the piston pin bore I.D. (page 13-7).

Inspect the connecting rod small end I. D. (page 13-10).

PISTON PIN-TO-PISTON PIN BORE

CLEARANCE

Subtract the piston pin O.D. from the piston pin bore

I.D. to obtain the piston pin-to-piston pin bore clearance.

STANDARD: 0.002 – 0.014 mm (0.0001 – 0.0006 in)


If the calculated clearance is more than the service limit,

replace the piston pin (page 13-5) and recheck the

clearance.


the new piston pin, replace the piston (page 13-5).

PISTON RING SIDE CLEARANCE

Measure the clearance between each piston ring and ring groove of the piston using a feeler gauge.

WB20XT2:

STANDARD:

Top: 0.035 – 0.070 mm (0.0014 – 0.0028 in)

Second: 0.045 – 0.080 mm (0.0018 – 0.0032 in)

SERVICE LIMIT:

Top: 0.15 mm (0.006 in)

Second: 0.15 mm (0.006 in)

WB30XT2:

STANDARD:

Top: 0.060 – 0.095 mm (0.0024 – 0.0037 in)

Second: 0.045 – 0.080 mm (0.0018 – 0.0032 in)

SERVICE LIMIT:

Top: 0.15 mm (0.006 in)

Second: 0.15 mm (0.006 in)

If any of the measurements is more than the service

limit, inspect the piston ring width (page 13-9).

If the piston ring width is normal, replace the piston

(page 13-5) and reinspect the clearance.

If necessary, replace the piston rings (top, second, oil) as a set and reinspect the clearance.

If any of the measurements is still more than the service

limit with the new piston rings, replace the piston (page

13-5).

13-8



PISTON RING WIDTH

Measure each piston ring width.

WB20XT2:

STANDARD:

Top: 0.950 – 0.970 mm (0.0374 – 0.0382 in)

Second: 0.940 – 0.960 mm (0.0370 – 0.0378 in)

SERVICE LIMIT:

Top: 0.93 mm (0.037 in)

Second: 0.92 mm (0.036 in)

WB30XT2:

STANDARD:

Top: 0.925 – 0.945 mm (0.0364 – 0.0372 in)

Second: 0.940 – 0.960 mm (0.0370 – 0.0378 in)

SERVICE LIMIT:

Top: 0.905 mm (0.0356 in)

Second: 0.92 mm (0.036 in)

If any of the measurements is less than the service limit,

replace the piston rings (top, second, oil) as a set (page

13-5).

PISTON RING END GAP

Before inspection, check whether the cylinder sleeve

I.D. is within the specification (page 13-6).

Measure each piston ring end gap using a feeler gauge.

WB20XT2:

STANDARD:

Top:

Second:

0.200 – 0.350 mm

(0.0079 – 0.0138 in)

0.350 – 0.500 mm

(0.0138 – 0.0197 in)

Oil (side rail): 0.2 – 0.7 mm

(0.01 – 0.03 in)

SERVICE LIMIT:

Top:

Second:

1.0 mm (0.04 in)

1.0 mm (0.04 in)

Oil (side rail): 1.0 mm (0.04 in)

WB30XT2:

STANDARD:

Top:

Second:

0.200 – 0.350 mm

(0.0079 – 0.0138 in)

0.350 – 0.500 mm

(0.0138 – 0.0197 in)

Oil (side rail): 0.10 – 0.35 mm

(0.004 – 0.014 in)

SERVICE LIMIT:

Top:

Second:

1.0 mm (0.04 in)

1.0 mm (0.04 in)

Oil (side rail): 1.0 mm (0.04 in)

If any of the measurements is more than the service limit, replace the piston rings (top, second, oil) as a set

(page 13-5).

[1]

CRANKCASE

13-9

CRANKCASE

CONNECTING ROD BIG END SIDE

CLEARANCE

Measure the clearance between the connecting rod big end and crankshaft using a feeler gauge.

STANDARD: 0.1 – 0.4 mm (0.004 – 0.016 in)



replace the connecting rod (page 13-5) and recheck the

clearance.


the new connecting rod, replace the crankshaft (page

13-4).

CONNECTING ROD SMALL END I.D.

Measure the connecting rod small end I.D.

WB20XT2:

STANDARD: 13.005 – 13.020 mm

(0.5120 – 0.5126 in)


WB30XT2:

STANDARD: 18.005 – 18.020 mm

(0.7089 – 0.7094 in)



replace the connecting rod (page 13-5).

Inspect the piston pin O.D. (page 13-8).

CONNECTING ROD BIG END I.D.

Set the connecting rod lower to the connecting rod upper and tighten the connecting rod bolts to the specified torque.

TORQUE:

WB20XT2:

WB30XT2:

12 N·m (1.2 kgf·m, 9 lbf·ft)

9.8 N·m (1.0 kgf·m, 7.2 lbf·ft)

Measure the connecting rod big end I.D.

WB20XT2:

STANDARD: 26.020 – 26.033 mm

(1.0244 – 1.0249 in)


WB30XT2:

STANDARD: 30.020 – 30.033 mm

(1.1819 – 1.1824 in)



replace the connecting rod (page 13-5).


13-10


CRANK PIN O.D.

Measure the crank pin O.D. of the crankshaft.

WB20XT2:

STANDARD: 25.970 – 25.980 mm

(1.0224 – 1.0228 in)


WB30XT2:

STANDARD: 29.970 – 29.980 mm

(1.1799 – 1.1803 in)



replace the crankshaft (page 13-4).

CONNECTING ROD BIG END OIL

CLEARANCE

Clean all oil from the crank pin and connecting rod big end surface.

Place a piece of plastigauge on the crank pin, install the connecting rod upper and the connecting rod lower, and tighten the connecting rod bolts to the specified torque.

TORQUE:

WB20XT2:

WB30XT2:

12 N·m (1.2 kgf·m, 9 lbf·ft)

9.8 N·m (1.0 kgf·m, 7.2 lbf·ft)

Do not rotate the crankshaft while the plastigauge is in place.

Remove the connecting rod and measure the plastigauge.

STANDARD: 0.040 – 0.063 mm (0.0016 – 0.0025 in)


If the clearance is more than the service limit, inspect

the connecting rod big end I.D. (page 13-10) and the

crank pin O.D.

If necessary replace the part that is not within the service limit and reinspect the clearance.

CRANKSHAFT RUNOUT

Set the crankshaft on V-blocks and measure the runout using a dial indicator.


If the measured runout is more than the service limit, replace the crankshaft.

CRANKCASE

15.0 mm (0.59 in) 14.0 mm (0.55 in)

13-11

CRANKCASE

CAMSHAFT CAM HEIGHT

Measure the cam height of the camshaft.

WB20XT2:

STANDARD:

IN: 27.600 – 27.800 mm (1.0866 – 1.0945 in)

EX: 27.647 – 27.847 mm (1.0885 – 1.0963 in)

SERVICE LIMIT:

IN: 27.450 mm (1.0807 in)

EX: 27.500 mm (1.0827 in)

WB30XT2:

STANDARD:

IN/EX: 27.603 – 27.703 mm (1.0867 – 1.0907 in)

SERVICE LIMIT:

IN/EX: 27.450 mm (1.0807 in)


replace the camshaft (page 13-4).

CAMSHAFT O.D.

Measure the O.D. of the camshaft.

STANDARD: 13.966 – 13.984 mm (0.5498 – 0.5506 in)




DECOMPRESSOR WEIGHT

Check for worn and weakened spring.

If the return spring (1) is worn or weakened, replace the weight return spring.

Check that the decompressor weight moves smoothly.

If the decompressor weight does not move correctly,



(1)

13-12


CRANKSHAFT BEARING

Turn the inner race of the bearing with your finger and check for play.

Replace the bearing if it is noisy or has excessive play.

CRANKCASE

CRANKSHAFT BEARING/OIL SEAL

REPLACEMENT

CRANKSHAFT BEARING

CRANKCASE SIDE/CYLINDER BARREL SIDE

Remove the oil seal and drive out the crankshaft bearing.

Drive a new crankshaft bearing (1) until it is fully seated on the end using the special tools.

TOOLS: WB20XT2 (62/22):

Attachment, 45 x 50 mm (2)

Pilot, 22 mm (3)

Driver (4)

07946-6920100

07746-0041000

07749-0010000

TOOLS: WB30XT2 (6205):

Attachment, 52 x 55 (2)

Pilot, 25 mm (3)

Driver (4)

07746-0010400

07746-0040600

07749-0010000

(4)

(2)

(3)

(1)

13-13

CRANKCASE

CRANKSHAFT OIL SEAL

CRANKCASE SIDE

Remove the oil seal.

Drive a new oil seal (1) in the position as shown using the special tools.

INSTALLATION HEIGHT:

WB20XT2: 5.0 mm (0.20 in)

WB30XT2: 5.5 mm (0.22 in)

(3)

(2)

TOOLS:


Driver (3)

07746-0010200

07749-0010000

CYLINDER BARREL SIDE

Remove the oil seal.

Drive a new oil seal (1) in the position as shown using the special tools.

INSTALLATION HEIGHT: 1.5 mm (0.06 in)

TOOLS: WB20XT2:


Driver (3)

TOOLS: WB30XT2:


Driver (3)

07746-0010100

07749-0010000

07746-0010200

07749-0010000


(1)

13-14

dummytext

14. MUFFLER

MUFFLER REMOVAL/INSTALLATION······14-2

EXHAUST PIPE STUD BOLT

REPLACEMENT ········································· 14-3

14

14-1

MUFFLER

MUFFLER

MUFFLER REMOVAL/INSTALLATION

The muffler becomes very hot during operation and remains hot for a while after stopping the engine.

Be careful not to touch the muffler while it is hot.

Allow it to cool before proceeding.

SCREW (5 x 8 mm) (4)


MUFFLER PROTECTOR

MUFFLER

14-2

NUT (8 mm) (2)

24 N·m (2.4 kgf·m, 18 lbf·ft)

EXHAUST PIPE GASKET


EXHAUST PIPE STUD BOLT

REPLACEMENT

Remove the muffler (page 14-2).

Thread two nuts onto the exhaust pipe stud bolt (1) and tighten them together, and then use a wrench to turn the stud bolt out.

Install and tighten the new stud bolts until they are the specified length.

SPECIFIED LENGTH: 15 mm (0.6 in)

(1)

SPECIFIED LENGTH

MUFFLER

14-3

MEMO

dummytext

WIRING DIAGRAM······································15-2

15. WIRING DIAGRAM

15

15-1

WIRING DIAGRAM

WIRING DIAGRAM

WIRING DIAGRAM


Bl

SPARK PLUG IGNITION COIL

ENGINE STOP SWITCH

IG E

OFF

ON

ENGINE STOP SWITCH OIL ALERT UNIT OIL LEVEL SWITCH

Bl

Y

Bu

G

R

W

Black

Yellow

Blue

Green

Red

White

Br

O

Lb

Brown

Orange

Light blue

Lg Light green

P Pink

Gr Gray

15-2

A

B

AIR CLEANER CHECK/CLEANING ················ 3-4

AIR CLEANER REMOVAL/INSTALLATION ···················

BEFORE TROUBLESHOOTING ························

6-5

············4-2

C

CARBURETOR BODY CLEANING ·················

CARBURETOR INSPECTION ····························

6-8

CARBURETOR DISASSEMBLY/ASSEMBLY ················

············6-8

6-6

CARBURETOR STUD BOLT REPLACEMENT············6-10

6-10

COMBUSTION CHAMBER CLEANING ·························

CONTROL BASE DISASSEMBLY/ASSEMBLY ·············7-3

COOLING FAN/FLYWHEEL REMOVAL/

INSTALLATION···················································

CRANKCASE COVER REMOVAL/INSTALLATION·····13-3

CRANKCASE COVER/CYLINDER BARREL/PISTON/

CONNECTING ROD/CRANKSHAFT/CAMSHAFT

INSPECTION ······················································

CRANKSHAFT BEARING/

···········13-13

CRANKSHAFT/PISTON REMOVAL/INSTALLATION ··13-4

CYLINDER HEAD DISASSEMBLY/ASSEMBLY ··········12-4

CYLINDER HEAD REMOVAL/INSTALLATION············12-3

D

CYLINDER HEAD/VALVES INSPECTION ···················

E

DIMENSIONAL DRAWINGS····························

3-3

ENGINE REMOVAL/INSTALLATION ···························

ENGINE STOP SWITCH INSPECTION ······················· 8-10

ENGINE STOP SWITCH REMOVAL/INSTALLATION ···8-6

············4-2

EXHAUST PIPE STUD BOLT REPLACEMENT···········14-3

F

FAN COVER REMOVAL/INSTALLATION ······················

FUEL TANK AND FILTER CLEANING ···························

G

3-9

FUEL TANK REMOVAL/INSTALLATION ·······················

FUEL TUBE CHECK···················

GOVERNOR ADJUSTMENT ······························

3-10

············7-4

I

H

GOVERNOR ARM/CONTROL BASE REMOVAL/

INSTALLATION···················································

GOVERNOR DISASSEMBLY/ASSEMBLY ····················

HARNESS AND TUBE ROUTING ··················· 2-8

IDLE SPEED CHECK/ADJUSTMENT ····························

IGNITION COIL AIR GAP CHECK/ADJUSTMENT ········8-7

IGNITION COIL REMOVAL/INSTALLATION··················

IGNITION SYSTEM TROUBLESHOOTING ···················

IMPELLER CHECK·····················

···············

8-2

··································

INDEX

L

M

3-11

IMPELLER/END PLATE REMOVAL/INSTALLATION··10-7

INLET PIPE/OUTLET PIPE REMOVAL/

INSTALLATION ··············································

LUBRICATION & SEAL POINTS························

MAINTENANCE SCHEDULE····························· ············3-2

MAINTENANCE STANDARDS ··························

MAXIMUM SPEED ADJUSTMENT····················

MECHANICAL SEAL REPLACEMENT························

MUFFLER REMOVAL/INSTALLATION························

O

14-2

OIL ALERT UNIT INSPECTION···································

OIL ALERT UNIT REMOVAL/INSTALLATION···············8-7

············8-9

OIL LEVEL SWITCH REMOVAL/INSTALLATION ·········8-6

P

PERFORMANCE CURVES································ ············1-4

PILOT SCREW REPLACEMENT·······················

PISTON DISASSEMBLY/ASSEMBLY··························

PUMP CASE/IMPELLER COVER REMOVAL/

INSTALLATION ··············································

13-5

R

··············10-5

PUMP INLET VALVE CHECK························

RECOIL STARTER DISASSEMBLY/ASSEMBLY··········9-3

············9-6

RECOIL STARTER REMOVAL/INSTALLATION ···········9-2

S

SEDIMENT CUP CLEANING ····························· ············3-6

SERIAL NUMBER LOCATION···························

SPARK PLUG CAP INSPECTION ························

SPARK PLUG CHECK/ADJUSTMENT··························

SPARK PLUG REPLACEMENT·························

3-5

············3-5

····························

SPECIFICATIONS·························

SYSTEM DIAGRAM ······················

T

TOOLS

CRANKCASE····························

CYLINDER HEAD················· ·····················

FUEL SYSTEM ·························

PUMP··················· ························

SERVICE INFORMATION ·····························

TORQUE VALUES ····················

············2-6

·························

V

VACUUM TEST·························

············2-4

··············10-9

VALVE CLEARANCE CHECK/ADJUSTMENT ··············3-7

··············12-9

VALVE GUIDE REPLACEMENT····················

W

··············12-8

VALVE SEAT RECONDITIONING ·····························

WATER PUMP TROUBLESHOOTING ··························

························

4-6

··············15-2

16

16-1

Honda WB20XT2, WB30XT2 Manual 132 Pages

Honda WB20XT2, WB30XT2 Manual

A Few Words About Safety

OUTLINE OF CHANGES

CONTENTS

INTRODUCTION

SERVICE RULES

SYMBOLS

ABBREVIATIONS

SERIAL NUMBER LOCATION

SPECIFICATIONS

SPECIFICATIONS

PERFORMANCE CURVES

PERFORMANCE CURVES

DIMENSIONAL DRAWINGS

DIMENSIONAL DRAWINGS

MAINTENANCE STANDARDS

TORQUE VALUES

LUBRICATION & SEAL POINTS

TOOLS

HARNESS AND TUBE ROUTING

MAINTENANCE SCHEDULE

ENGINE OIL LEVEL CHECK/CHANGE

AIR CLEANER CHECK/CLEANING

SPARK PLUG CHECK/ADJUSTMENT

SPARK PLUG REPLACEMENT

SEDIMENT CUP CLEANING

IDLE SPEED CHECK/ADJUSTMENT

VALVE CLEARANCE CHECK/

ADJUSTMENT

COMBUSTION CHAMBER CLEANING

FUEL TANK AND FILTER CLEANING

FUEL TUBE CHECK

IMPELLER CHECK

IMPELLER CLEARANCE CHECK

PUMP INLET VALVE CHECK

IMPELLER CLEARANCE CHECK

BEFORE TROUBLESHOOTING

ENGINE TROUBLESHOOTING

WATER PUMP TROUBLESHOOTING

FAN COVER REMOVAL/INSTALLATION

TOOLS

FUEL TANK REMOVAL/INSTALLATION

AIR CLEANER

REMOVAL/INSTALLATION

CARBURETOR

REMOVAL/INSTALLATION

CARBURETOR DISASSEMBLY/ASSEMBLY

CARBURETOR BODY CLEANING

CARBURETOR INSPECTION

PILOT SCREW REPLACEMENT

CHOKE REPLACEMENT

CARBURETOR STUD BOLT

REPLACEMENT

GOVERNOR ARM/CONTROL BASE

REMOVAL/INSTALLATION

CONTROL BASE

DISASSEMBLY/ASSEMBLY

GOVERNOR ADJUSTMENT

GOVERNOR

DISASSEMBLY/ASSEMBLY

MAXIMUM SPEED ADJUSTMENT

SYSTEM DIAGRAM

IGNITION SYSTEM TROUBLESHOOTING

IGNITION COIL

REMOVAL/INSTALLATION

COOLING FAN/FLYWHEEL

REMOVAL/INSTALLATION

OIL LEVEL SWITCH

REMOVAL/INSTALLATION

ENGINE STOP SWITCH

REMOVAL/INSTALLATION

OIL ALERT UNIT

REMOVAL/INSTALLATION

IGNITION COIL AIR GAP

CHECK/ADJUSTMENT

SPARK TEST

SPARK PLUG CAP INSPECTION

IGNITION COIL INSPECTION

OIL LEVEL SWITCH INSPECTION