- 43 -
A
bn
o
rm
a
l
eng
ine
o
per
a
ti
o
n
Abnormal noise
from engine
1
、
Serious
worn
out
cylinder and piston
2
、
Serious worn out needle
bearings in small and big
ends of connecting rod
3
、
Premature ignition
4
、
Excessive carbon deposit
in combustion chamber
5
、
Overheated spark plug
1
、
Replace cylinder body
and piston
2
、
Replace bearing and
relate parts
3
、
Adjust ignition time
4
、
Clean
out
carbon
deposit
5
、
Replace spark plug
Unstable engine
operation
1
、
Water
or
dirt
in
carburetor
2
、
Clogged fuel passage
3
、
Leaking crankcase
4
、
Leaking
connection
between carburetor and
engine
5
、
Over-rich or over-thin
gas mixture
1
、
Clean the carburetor
2
、
Clean or replace fuel
pipe
3
、
Replace sealing
4
、
Tighten screw
5
、
Adjust carburetor
Overheat engine
1
、
Low gear driving over a
long time
2
、
Over loaded driving or
long time driving with
heavy load
3
、
Over-rich or over-thin
gas mixture
4
、
Unqualified engine oil or
insufficient transmission
oil
5
、
Slipping clutch
6
、
Too tight chain
7
、
Unreleased brake
1
、
Change
gear
position
and control
time
2
、
Control
load-carrying and rest
from time to time for
cooling
3
、
Adjust carburetor
4
、
Replace
with
qualified engine oil and
fill oil to transmission
case
5
、
Adjust free play or
replace clutch, friction
lining and spring
6
、
Adjust tension
7
、
Adjust
brake
clearance
