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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 non-
permanent 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.