- 41 -
A
bn
o
rm
a
l
eng
ine
o
p
er
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
deposits 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
fuel mixture
1
、
Clean the carburetor
2
、
Clean or replace fuel
pipe
3
、
Replace sealing
4
、
Tighten screw
5
、
Adjust carburetor
