All rights reserved. No parts of this publication may be reproduced, stored in a retrieval system, or transmitted in any
form or by any means, electronic mechanical photocopying, recording or otherwise, without the prior written permission of
Quality Assurance Department/Consumer Products & Machinery Group/Kawasaki Heavy Industries, Ltd., Japan.
No liability can be accepted for any inaccuracies or omissions in this publication, although every possible care has been
taken to make it as complete and accurate as possible.
The right is reserved to make changes at any time without prior notice and without incurring an obligation to make such
changes to products manufactured previously.
All information contained in this publication is based on the latest product information available at the time of publication.
Illustrations and photographs in this publication are intended for reference use only and may not depict actual model
component parts.
Aampere(s)lbpound(s)
ABDCafter bottom dead centermmeter(s)
ACalternating currentminminute(s)
ATDCafter top dead centerNnewton(s)
BBDCbefore bottom dead centerPapascal(s)
BDCbottom dead centerPShorsepower
BTDCbefore top dead centerpsipound(s) per square inch
C
DCdirect currentrpmrevolution(s) per minute
Ffarad(s)TDCtop dead center
To protect the environment in which we all live, Kawasaki has incorporated crankcase emission (1) and exhaustemission
(2) control systems (EM) in compliance with applicable regulations of the United States Environmental Protection Agency
and California Air Resources Board.
1. Crankcase Emission Control System
A sealed-type crankcase emission control system is used to eliminate blow-by gases. The blow-by
gases are led to the breather chamber through the crankcase. Then, it is led to the air cleaner.
Oil is separated from the gases while passing through the inside of the breather chamber from the
crankcase, and then returned back to the bottom of crankcase.
2. Exhaust Emission Control System
The exhaust emission control system applied to this engine consists of a carburetor and an ignition
system having optimum ignition timing characteristics.
The carburetor has been calibrated to provide lean air/fuel mixture characteristics and optimum fuel
economy with a suitable air cleaner and exhaust system.
TAMPERING WITH EMISSION CONTROL SYSTEM PROHIBITED
Federal law and California State law prohibits the following acts or the causing thereof: (1) the removal or rendering
inoperative by any person other than for purposes of maintenance, repair, or replacement, of any device or element of
design incorporated into any new engine for the purpose of emission control prior to its sale or delivery to the ultimate
purchaser or while it is in use, or (2) the use of the engine after such device or element of design has been removed or
rendered inoperative by any person.
Among those acts presumed to constitute tampering are the acts listed below:
Do not tamper with the original emission related part:
Carburetor and internal parts
•
Spark plugs
•
Magneto or electronic ignition system
•
Fuel filter element
•
Air cleaner elements
•
Crankcase
•
Cylinder heads
•
Breather chamber and internal parts
•
Intake pipe and tube
•
Foreword
This manual is designed primarily for use by trained
mechanics in a properly equipped shop.However, it
contains enough detail and basic information to make
it useful to the owner who desires to perform his own
basic maintenance and repair work. A basic knowledge
of mechanics, the proper use of tools, and workshop
procedures must be understood in order to carry out
maintenance and repair satisfactorily.Whenever the
owner has insufficient experience or doubts as to his
ability to do the work, all adjustments, maintenance, and
repair should be carried out only by qualified mechanics.
In order to perform the work efficiently and to avoid
costly mistakes, read the text, thoroughly familiarize
yourself with the procedures before starting work, and
then do the work carefully in a clean area. Whenever
special tools or equipment are specified, do not use
makeshift tools or equipment. Precision measurements
can only be made if the proper instruments are used,
and the use of substitute tools may adversely affect safe
operation.
To get the longest life out of your engine:
Follow the Periodic Maintenance Chart in the Service
•
Manual.
Be alert for problems and non-scheduled maintenance.
•
Use proper tools and genuine Kawasaki engine parts.
•
Genuine parts provided as spare parts are listed in the
Parts Catalog.
Follow the procedures in this manual carefully. Don’t
•
take shortcuts.
Remember to keep complete records of maintenance
•
and repair with dates and any new parts installed.
If you want spark plug information, for example, go to
the Periodic Maintenance Chart first. The chart tells you
how frequently to clean and gap the plug. Next, use the
Quick Reference Guide to locate the Electrical System
chapter. Then, use the Tableof Contents on the first page
of the chapter to find the Spark Plug section.
Whenever you see these WARNING and CAUTION
symbols, heed their instructions!Always follow safe
operating and maintenance practices.
This warning symbol identifies special instruc-
tions or procedures which, if not correctly fol-
lowed, could result in personal injury, or loss of
life.
CAUTION
This caution symbol identifies special instruc-
tions or procedures which, if not strictly ob-
served, could result in damage to or destruction
of equipment.
This manual contains four more symbols (in addition to
WARNING and CAUTION) which will help you distinguish
different types of information.
NOTE
This note symbol indicates points of particular interest for more efficient and convenient operation.
How to Use This Manual
In preparing this manual, we divided the product into
its major systems. These systems became the manual’s
chapters. All information for a particular system from
adjustment through disassembly and inspection is located
in a single chapter.
The Quick Reference Guide shows you all of the
product’s system and assists in locating their chapters.
Each chapter in turn has its own comprehensive Table of
Contents.
The Periodic Maintenance Chart is located in the
General Information chapter.The chart gives a time
schedule for required maintenance operations.
Indicates a procedural step or work to be done.
•
Indicates a procedural sub-step or how to do the work
of the procedural step it follows. It also precedes the
text of a WARNING, CAUTION, or NOTE.
Indicates a conditionalsteporwhataction to take based
on the results of the test or inspection in the procedural
step or sub-step it follows.
In most chapters an exploded view illustration of the
system components follows the Table of Contents. In
these illustrations you will find the instructions indicating
which parts require specified tightening torque, oil, grease
or a locking agent during assembly.
GENERAL INFORMATION 1-1
General Information
Table of Contents
Before Servicing.................................................................................................................................................................1-2
Model Identification............................................................................................................................................................1-4
General Specifications.......................................................................................................................................................1-6
Torque and Locking Agent.................................................................................................................................................1-9
Special Tools....................................................................................................................................................................1-13
1
1-2 GENERAL INFORMATION
Before Servicing
Before starting to service the engine, carefully read the applicable section to eliminate unnecessary work. Photographs,
diagrams, notes, cautions, warnings, and detailed descriptions have been included wherever necessary. Nevertheless,
even a detailed account has limitations, a certain amount of basic knowledge is required for successful work.
Especially note the following:
(1) Dirt
Before removal and disassembly, clean the engine. Any dirt entering the engine, carburetor, or other parts, will
work as an abrasive and shorten the life of engine. For the same reason, before installing a new part, clean off any
dust or metal filings.
(2) Battery Ground
Remove the ground (—) lead from the battery before performing any disassembly operations on the equipment.
This prevents:
(a) the possibility of accidentally turning the engine over while partially disassembled.
(b) sparks at electrical connections which will occur when they are disconnected.
(c) damage to electrical parts.
(3) Tightening Sequence
Generally, when installing a part with several bolts, nuts, or screws, start them all in their holes and tighten them to
a snug fit. Then tighten them evenly, in a staggered sequence. This is to avoid distortion of the part and/or causing
gas or oil leakage. Conversely when loosening the bolts, nuts, or screws, first loosen all of them by about a quarter
of a turn and then remove them. Where there is a tightening sequence indication in this Service Manual, the bolts,
nuts, or screws must be tightened in the order and method indicated.
(4) Torque
When torque values are given in this Service Manual, use them. Either too little or too much torque may lead to
serious damage. Use a good quality, reliable torque wrench.
(5) Force
Common sense should dictate how much force is necessary in assembly and disassembly. If a part seems especially
difficult to remove or install, stop and examine what may be causing the problem. Whenever tapping is necessary, tap
lightly using a wooden or plastic-faced mallet. Use an impact driver for screws (particularly for the removal of screws
held by a locking agent) in order to avoid damaging the heads.
(6) Edges
Watch for sharp edges, especially during major engine disassembly and assembly. Protect your hands with gloves
or a piece of thick cloth when lifting the engine or turning it over.
(7) High-Flash Point Solvent
A high-flash point solvent is recommended to reduce fire danger. A commercial solvent commonly available in North
America is Standard solvent (generic name). Always follow manufacturer and container directions regarding the use
of any solvent.
(8) Gasket, O-Ring
Do not reuse a gasket or O-ring once it has been in service. The mating surfaces around the gasket should be
free of foreign matter and perfectly smooth to avoid oil or compression leaks.
(9) Liquid Gasket, Non-Permanent Locking Agent
Follow manufacturer’s directions for cleaning and preparing surfaces where these compounds will be used. Apply
sparingly. Excessive amounts may block engine oil passages and cause serious damage. An example of a nonpermanent locking agent commonly available in North America is Loctite Lock’n Seal (Blue).
(10) Press
A part installed using a press or driver, such as a journal, should first be coated with oil on its outer or inner
circumference so that it will go into place smoothly.
(11) Ball Bearing
When installing a ball bearing, the bearing race which is affected by friction should be pushed by a suitable driver.
This prevents severe stress on the balls and races, and prevents races and balls from being dented. Press a ball
bearing until it stops at the stop in the hole or on the shaft.
(12) Oil Seal and Grease Seal
Replace any oil or grease seals that were removed with new ones, as removal generally damages seals.
When pressing in a seal which has manufacturer’s marks, press it in with the marks facing out. Seals should be
pressed into place using a suitable driver, which contacts evenly with the side of seal, until the face of the seal is even
with the end of the hole.
(13) Seal Guide
A seal guide is required for certain oil or grease seals during installation to avoid damage to the seal lips. Before
a shaft passes through a seal, apply a little oil, preferably high temperature grease on the lips to reduce rubber to
metal friction.
(14) Circlip, Retaining Ring
Replace any circlips and retaining rings that were removed with new ones, as removal weakens and deforms them.
When installing circlips and retaining rings, take care to compress or expand them only enough to install them and
no more.
GENERAL INFORMATION 1-3
Before Servicing
(15) Cotter Pin
Replace any cotter pins that were removed with new ones, as removal deforms and breaks them.
(16) Lubrication
Engine wear is generally at its maximum while the engine is warming up and before all the rubbing surfaces have
an adequate lubricative film. During assembly, oil or grease (whichever is more suitable) should be applied to any
rubbing surface which has lost its lubricative film. Old grease and dirty oil should be cleaned off. Deteriorated grease
has lost its lubricative quality and may contain abrasive foreign particles.
Don’t use just any oil or grease. Some oils and greases in particular should be used only in certain applications and
may be harmful if used in an application for which they are not intended. This manual makes reference to molybdenum
disulfide grease (MoS2) in the assembly of certain engine parts. Always check manufacturer recommendations before
using such special lubricants.
(17) Electrical Wires
All the electrical wires are either single-color or two-color and, with only a few exceptions, must be connected to
wires of the same color. On any of the two-color wires there is a greater amount of one color and a lesser amount of
a second color, so a two-color wire is identified by first the primary color and then the secondary color. For example,
a yellow wire with thin red stripes is referred to as a "yellow/red" wire; it would be a "red/yellow" wire if the colors were
reversed to make red the main color.
(18) Replacement Parts
When there is a replacement instruction, replace these parts with new ones every time they are removed. There
replacement parts will be damaged or lose their original function once removed.
(19) Inspection
When parts have been disassembled, visually inspect these parts for the following conditions or other damage. If
there is any doubt as to the condition of them, replace them with new ones.
AbrasionCrackHardeningWarp
BentDentScratchWear
Color changeDeteriorationSeizure
(20) Specifications
Specification terms are defined as follows:
"Standards" show dimensions or performances which brand-new parts or systems have.
"Service Limits" indicate the usable limits. If the measurement shows excessive wear or deteriorated performance,
replace the damaged parts.
1-4 GENERAL INFORMATION
Model Identification
Electric Starter Model-FH500V
Recoil Starter Model-FH500V
Cylinder Number Designation:
No.1 Cylinder is the left-hand cylinder viewed from the air cleaner.
No.2 Cylinder is the right-hand cylinder viewed from the air cleaner.
Model Identification
Electric Starter Model-FH680V
GENERAL INFORMATION 1-5
1-6 GENERAL INFORMATION
General Specifications
Items
Type of engine
Cylinder layout90 V-Twin
Bore x Stroke68 mm x 68 mm (2.68 in x 2.68 in) 75.2 mm x 76 mm (2.96 in x 2.99 in)
Piston displacement494 mL (30.1 cu. in)675 mL (41.19 cu.in)
Direction of rotationCounterclockwise facing the PTO shaft
Compression releaseAutomatic compression release
Low idle speed1550 rpm
Fast idle speed3600 rpm
Ignition systemTransistorized-fly wheel magneto
RFIPer Canada and U.S.A. requirements
Starting systemElectric starter and/or recoil starter
Charging system12 V - 13 amps with regulator
Spark plugCHAMPION RCJ8YNGK BPR4ES
CarburetorFloat type, fixed main jetFloat type, fixed main jet, two barrel
Fuel pumpDiaphragm type pulse pump
Air cleanerDual stage element, dry type
GovernorFlyweight all speed governor
Lubrication systemPressure feed by positive displacement pump
Oil filterCartridge type full flow filter
Oil pressuer switchON-OFF switch
Oil capacity
(when engine is
completely dry)
Cooling systemForced air cooling by fan
Dimensions (L x W x H )425 mm x 359 mm x 324 mm458 mm x 430 mm x 381mm
Electric starter model(16.7 in x 14.1 in x 12.8 in)(18.0 in x 16.9 in x 15.0 in)
Recoil starter model(16.7 in x 14.1 in x 14.2 in)
Dry weight
Electric starter model34 kg (75 lb)40.5 kg (89.3 lbs)41.2 kg
Recoil starter model32 kg (71 lb)
Specifications are subject to change without notice.
GENERAL INFORMATION 1-7
Periodic Maintenance Chart
To ensure satisfactory operation over an extended period of time, any engine requires normal maintenance regular
intervals. The Periodic Maintenance Chart below shows periodic inspection and maintenance items and suitable intervals.
The bullet mark (•) designates that the corresponding item should be performed at that interval.
Some adjustments require the use of special tools or other equipment. An electronic tachometer will facilitate setting
idle and running speeds.
FH451V, FH500V, FH531V
OPERATIONINTERVAL
DailyFirst
Check or clean air intake screen
Check and add engine oil
Check for fuel and oil leakage
Check for loose or lost nut and screw
Check battery electrolyte level
Clean air cleaner foam element (1)
Clean air cleaner paper element (1)
Clean dust and dirt from cylinder and
cylinder head fins (1)
Tighten nut and screws
Change engine oil
Clean and re-gap spark plugs
Change Oil filter
Change air cleaner paper element (1)
Check and adjust vlave clearance
Clean and lap valve seating surface
Clean combustion chamber
(1): Service more frequently under dusty conditions.
: These items must be performed with the proper tools. See your authorized Kawasaki Engine Dealer for service,
unless you have the proper equipment and mechanical proficiency.
•
•
•
•
•
8hr.
••
Every
25 hr.
•
Every
50 hr.
•
Every
100 hr.
•
•
•
Every
200 hr.
•
•
Every
300 hr.
•
•
•
1-8 GENERAL INFORMATION
Periodic Maintenance Chart
FH601V, FH641V, FH680V, FH721V
OPERATION
DailyFirst
Check or clean air intake screen
Check and add engine oil
Check for fuel and oil leakage
Check for loose or lost nut and screw
Check battery electrolyte level
Clean air cleaner foam element (1)
Clean air cleaner paper element (1)
Clean dust and dirt from cylinder and
cylinder head fins (1)
Tighten nut and screws
Change engine oil
Clean and re-gap spark plugs
Check and clean oil cooler fins (FH721V
engines).
Change Oil filter
Change air cleaner paper element (1)
Check and adjust vlave clearance
Clean and lap valve seating surface
Clean combustion chamber
(1): Service more frequently under dusty conditions.
: These items must be performed with the proper tools. See your authorized Kawasaki Engine Dealer for service,
unless you have the proper equipment and mechanical proficiency.
•
•
•
•
•
8hr.
••
Every
25 hr.
•
INTERVAL
Every
50 hr.
Every
100 hr.
•
•
•
•
•
Every
200 hr.
•
•
Every
300 hr.
•
•
•
GENERAL INFORMATION 1-9
Torque and Locking Agent
The following tables lists the tightening torque for the major fasteners, and the parts requiring use of a non-permanent
locking agent or liquid gasket.
Letters used in the "Remarks" column mean:
L:Apply a non-permanent locking agent to the threads.
M:Apply a molybdenum disulfide lubricant (grease or oil) to the threads, seated surface, or washer.
O:Apply an oil to the threads, seated surface, or washer.
S:Tighten the fasteners following the specified sequence.
SS : Apply silicone sealant.
FH451V, FH500V, FH531V
Fastener
Fuel System:
Choke Valve Screw0.70.076in1lb
Throttle Valve Screws1.00.109in
Pilot Jet1.70.1715 in
Main Jet0.70.076in1lb
Main Air Jet0.70.076in
Main Nozzle2.00.2017 in1lb
Pilot Air Jet0.70.076in
Drain Screw (Carburetor)1.30.1311 in
Earth Lead Screw3.40.3530 in
(Carburetor Side)
Fuel Shut Off Solenoid Valve6.90.7061 in
(Carburetor)
Float Chamber Mounting Screw8.80.9078 in-lb
(Carburetor)
Governor Arm Clamp Nut7.80.869 in1lb
Governor Shaft Plate Screws2.00.2018 in-lb
Holder Plate Nuts (Air Cleaner,5.90.6052 in
Carburetor Mounting)
Intake Manifold Mounting Bolts5.90.652 in
Cleaner Body Mounting Screws3.40.3530 in
Control Panel Mounting Bolts5.90.652 in1lb
Choke Valve Screw1.00.108.9 in
Throttle Valve Screws
Pilot Jet–––
Main Jet––Plug, Main Jet191.914
Main Nozzle–––
Main Air Jet–––
Pilot Air Jet–––
Drain Screw(Carburetor)2.00.218 in1lb
Earth lead screw–––
(Carburetor Side)
Fuel Shut Off Solenoid Valve (Carburetor)202.015
Float Chamber Mounting3.90.435 in1lb
Screw(Carburetor)
Governor Arm Clamp Nut7.80.869 in
Governor Shaft Plate Screws2.00.218 in
Intake Pipe Mounting Bolts and Nuts5.90.652 in1lb
Intake Manifold Mounting Bolts5.90.652 in1lb
Cleaner Body Mounting Screws–––
Control Panel Mounting Bolts5.90.652 in
Cooling System:
Engine-shroud Bolt (M8)151.511
Engine-shroud Bolts (M6)5.90.652 in
Plug Bolt (Engine-shroud)–––
Plug Screw (Engine-shroud)3.40.3530 in
Engine Top End:
Cylinder Head Bolts252.619=S
Valve Clearance Lock Screws6.90.761 in
Connecting Rod Big End212.115=O
Cap Bolts
Rocker Arm Bolts282.820
Rocker Cover Mounting Bolts5.90.652 in-lb
Exhaust Pipe Flange Nuts151.511
Spark Plugs222.216
Starter Coil Screws3.40.3530 in
Flywheel Bolt565.741
Fan Housing Bolts5.90.652 in1lb
Screen Bolts5.90.652 in
Regulator Screws3.40.3530 in
Ignition Coil Bolts (Studs)7.80.869 in1lb
Ignition Coil Bolts (Bolts)5.90.652 in
Starter Motor Mounting Bolts151.511
Recoil Starter Mounting Nuts–––
Recoil Starter Retainier Screw–––
Spark Plugs222.216
FH601V, FH641V, FH680V, FH721V
Torque
N1mkg1mft1lb
6.90.761 in1lb
9.81.087 in
252.619.0=S
Remarks
1
lb
1
lb
1
lb
1
lb
1
lb
=SS
L:Apply a non-permanent locking agent to the threads.
M:Apply a molybdenum disulfide lubricant (grease or oil) to the threads, seated surface, or washer.
O:Apply an oil to the threads, seated surface, or washer.
S:Tighten the fasteners following the specified sequence.
SS : Apply silicone sealant.
The table below, relating tightening torque to thread diameter, lists the basic torque for the bolts and nuts. Use this
table for only the bolts and nuts which do not require a specific torque value. All of the values are for use with dry
solvent-cleaned threads.
Housing (Case and Body) Inspection.................2-28
2-2 FUEL SYSTEM
Exploded View
[FH451V, FH500V, FH531V]
Exploded View
[FH451V, FH500V, FH531V]
1. Pilot Screw
2. Pilot Air Jet
3. Main Air Jet
4. Main Jet
5. Pilot Jet
6. Solenoid Valve
FUEL SYSTEM 2-3
T1: 0.7 N
T2: 1.0 N
T3: 1.3 N
T4: 1.7 N
T5: 2.0 N
T6: 3.4 N
T7: 3.9 N
T8: 6.9 N
T9: 7.8 N
T10: 8.8 N
1
m (0.07 kg
1
m (0.10 kg
1
m (0.13 kg
1
m (0.17 kg
1
m (0.20 kg
1
m (0.35 kg
1
m (0.40 kg
1
m (0.70 kg
1
m (0.80 kg
1
m (0.90 kg
1
m, 6 in
1
m, 9 in
1
m, 11 in
1
m, 15 in
1
m, 17 in
1
m, 30 in
1
m, 35 in
1
m, 61 in
1
m, 69 in
1
m, 78 in
1
lb)
1
lb)
1
lb)
1
lb)
1
lb)
1
lb)
1
lb)
1
lb
1
lb)
1
lb)
2-4 FUEL SYSTEM
Exploded View
[FH601V, FH641V, FH680V, FH721V]
Exploded View
[FH601V, FH641V, FH680V, FH721V]
1. Pilot Screw
2. Pilot Air Jet
3. Main Air Jet
4. Main Jet
5. Pilot Jet
6. Solenoid Valve
FUEL SYSTEM 2-5
T1: 1.0 N
T2: 3.9 N
T3: 2.0 N
T4: 19 N
T5: 20 N
T6: 6.9 N
1
m (0.10 kg
1
m (0.40 kg
1
m (0.20 kg
1
m (1.9 kg
1
m (2.0 kg
1
m (0.70 kg
1
m, 9 in
1
m, 35 in
1
m, 18 in
1
m, 14 ft
1
m, 15 ft
1
m, 61 in
1
lb)
1
lb)
1
lb)
1
lb)
1
lb)
1
lb)
2-6 FUEL SYSTEM
Exploded View
Exploded View
[FH451V, FH500V, FH531V]
T5: 2.0 N
T8: 5.9 N
T9: 7.8 N
[FH601V, FH641V, FH680V, FH721V]
T5: 2.0 N
T8: 5.9 N
T9: 7.8 N
O: Apply engine oil.
1
m (0.20 kg
1
m (0.60 kg1m , 52 in
1
m (0.80 kg1m , 69 in
1
m (0.20 kg
1
m (0.60 kg
1
m (0.80 kg1m , 69 in
1
m , 17 in
1
m , 17 in
1
m , 52 in
1
lb)
1
lb)
1
lb)
1
lb)
1
lb)
1
lb)
FUEL SYSTEM 2-7
2-8 FUEL SYSTEM
Specifications
Standard
Item
Caburetors Specifications:
Make/ typeMIKUNI B24T1
Throttle bore diameter24 mm (0.94 in.)
Venturi diameter16 mm (0.63 in.)18 mm (0.71 in.)21 mm (0.83 in.)
Main Jet (MJ)#125#116.3L: #136, R: #140
Pilot jet (PJ)#48.8#43.8L: #46, R: #44
Main air jet (MAJ)ø1.7ø1.4
Pilot air jet (PAJ)ø1.2ø0.8
Pilot air screw turns out (PS)2 1/41 3/8L: 2 1/4, R: 1 1/4
(Idle mixture screw turns out)
Float levelFloat parallel to carburetor body
Idle Speed: (1)
Low idle speed1550 r/min (rpm)
High idle speed3600 r/min (rpm)
Air Cleaner:
TypeDual stage filtration system
Pre-cleanerFoam element
Second-stage cleanerPaper element
Fuel:
Fuel requirementUnleaded regular grade gasoline
Fuel Pump:
TypePulse-diaphragm pump
Governor:
TypeFlyweight all speed governor
FH451V, FH500V,
FH531V
FH601V, FH641V, FH680V,
Nikki 621266
26 mm (1.02 in.)
1.7
1.1
FH721V
(1) Idle speeds may vary depending on each equipment. Refer to the equipment specification.
Governor Link Mechanism
Control Panel Assembly Removal
Remove:
•
Air Cleaner (see Cleaner Body Removal)
Air Cleaner Mount Bracket Bolts [A]
Air Cleaner Mount Bracket [B]
Earth Lead (Starter Model)
Control Panel Mounting Bolts [C]
Remove the control panel assembly [A] while unhooking the governor
•
spring [B] end loop at the panel bracket.
Clear the choke link rod lower end [C] from the choke lever.
•
FUEL SYSTEM 2-9
Control Panel Assembly Installation
Before installing the control panel assembly, check to see that the
•
choke lever [A] and engine speed control lever [B] move smoothly in
all directions.
If any part is worn or damaged, replace the control panel assembly.
After installation, adjust the low idle speeds and high idle speeds
•
to the specifications (see Low Idle Speed and High Idle Speed
adjustment).
Governor Arm Removal
Remove:
•
Control Panel Assembly
Loosen the clamp nut [A] and take off the governor arm [B].
•
Unhooking the throttle link rod spring [C] end loop and clear the
•
throttle link rod lower end [D].
2-10 FUEL SYSTEM
Governor Link Mechanism
Governor Arm Installation
Install the governor arm [A] onto the governor shaft [B] temporarily.
•
Be sure the link spring [C] around the throttle link rod [D] is inplace
•
and that it pulls the governor arm and throttle lever [E] each other.
Loosen the clamp nut [F] on the governor arm enough to move the
•
governor shaft.
Turn the top end of the governor arm counterclockwise to fully open
•
the carburetor [G] throttle valve and hold it there.
Turn the governor shaft counterclockwise, fully turn the shaft to end
•
of its travel.
Tighten the clamp nut.
•
Torque -Governor Arm Clamp Nut: 7.8 N1m (0.80 kg
Be sure the governor shaft extend from the governor arm is approxi-
•
mately 7 mm (0.3 in) [H] as shown.
Install the control panel assembly, and connect the governor arm with
•
the governor spring.
1
m, 69 in1lb)
Governor Assembly Removal
Remove the crankcase cover (see Camshaft/Crankshaft chapter).
•
Remove the push rod. (see Engine Top End chapter)
•
Upside down the engine.
•
Remove the camshaft [A].
•
Remove:
•
Washer [A]
Snap Ring [B]
Sleeve [C]
Governor Plate [D]
Snap Ring [B]
Steel balls [E]
Ball Guide [F]
Ball Plate [G]
Governor Assembly Installation
Fit the snap rings [A] into the grooves securely.
•
Spin the governor plate by hand and check that the steel balls and
•
governor plate operate freely.
Governor Link Mechanism
Governor Assembly Inspection
Visually check all governor parts for wear and damage.
If any parts are worm or damaged, replace them.
Governor Shaft Removal
Split the crankcase (see Camshaft/Crankcase chapter).
•
Unscrewthe governor shaft plate screws [A], and pull out the governor
•
shaft [B] outside.
NOTE
It is not necessary to remove the governor shaft unless it is being
replaced.
Replace the oil seal only if the lip shows signs of leakage or it has
•
been damaged.
The oil seal [A] must be assembled with seal lip towards inside of the
•
engine.
Press in the oil seal 0
•
crankcase surface [C].
1.0 mm (0.04 in.) [B] flush or below the
FUEL SYSTEM 2-11
Governor Shaft Installation
Apply engine oil to the governor shaft.
•
Insert the governor shaft into the crankcase.
•
Install the governor shaft plate [A] to the shaft [B] as shown.
Check that the governor shaft moves freely in its operating range.
•
NOTE
If the oil seal is removed, oil seal is put on after shaft is installed.
2-12 FUEL SYSTEM
Carburetor
Fuel and Air Flow
The main system of the carburetor consists of the main jet [A], Valve
seat [B] main nozzle [C], and the main air passage [D] (main air jet
[E]). The main system meters fuel to the engine during moderate to
heavy load conditions. Fuel flows through the main jet and into the
main nozzle, where it is joined by air from the main air passage (main
air jet). The resulting mixture flows out the end of the main nozzle into
the carburetor bore, where it is atomized by the high speed air flow, and
carried into the engine.
The pilot system includes the pilot jet [F], pilot screw [G] (Idle mixture
screw), pilot air jet [H], pilot outlet [I], and the bypass holes [J]. The pilot
system meters the fuel/air mixture while the engine is idling and running
under a light load. Under these conditions there is very little air flow
through the carburetor bore; so little that it is not enough to draw fuel
through the main system of the carburetor and atomize it. Instead, the
fuel is drawn through the pilot system, since the nearly closed throttle
valve [K] causes high speed air flow past the pilot outlet and bypass
holes (even at low engine speed).
Fuel flow in the pilot system is metered by the pilot jet. Air for better
atomization is admitted via the pilot air jet in the mouthof the carburetor.
The fuel/air mixture passes into the bore of the carburetor side stream
of the throttle valve through the bypass holes and pilot outlet. While
the throttle valve is almost closed, it covers the small bypass holes
opening into the bore from the pilot system. As the throttle valve begins
to open, it uncovers the bypass holes, allowing more fuel/air mixture to
flow. The extra flow is needed because the engine starts to run faster
as the throttle is opened. The pilot screw controls the amount of fuel/air
mixture allowed through the pilot outlet, but does not meter the bypass
holes. A moderate amount of air comes in around the throttle valve at
an idle, so adjusting the pilot screw changes the fuel/air ratio. Turning
the pilot screw (Idle mixture screw) out (Counterclockwise) enrichens
the mixture; turning it in (clockwise) leans the mixture.
Main Fuel Flow
Pilot Fuel Flow ⇒
!
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