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Make a spark-over test
to the spark plug
No spark or weak spark between poles of spark plug
Unscrew the spark plug cap, make a
spark-over test to high-voltage cable
There is a strong
blue spark
Check if the spark plug or
spark plug cap is faulty
Check if the
Check the
ignition coil is
ignition
short-circuited
power upply
o r o p e n -
circuited
Non-contact magneto
ignition system
1. Check if the ignition
power supply coil is
short-circuited or open-
circuited
2. Check if the trigger coil
is short-circuited or open-
circuited
S p a r k
p l u g
electrodes are damp
Check if the air
cleaner is clogged.
66
1.3 Fault diagnostic procedure for engine start failure or difficulty
The engine fails to start or has difficulty in start-up
Check the ignition system
Remove the spark plug and check if the electrodes
No
of spark plug are connected
No spark or weak spark
between poles of spark plug
C h e c k i f t h e
c i r c u i t i n t h e
ignition system
is short-circuited
or
S u f f i c i e n t
compression
pressure in
cylinder
R e m o v e a n d
check the spark
plug
Spark plug electrodes are dry
Drip a small amount of gasoline into the cylinder and try to start
Running time is very short
or it shuts down after start-up
Use the diagnostic
tool to check
There is a strong blue or bluish
violet spark between electrodes
Check if the engine ignition is normal
1.Check if the CDI ignition
is faulty
2.C h e c k t h e m a g n e t i c
motor flywheel and trigger
coil for any looseness
Use a cylinder pressure
U s e a c y l i n d e r
C h e c k i f t h e
g a u g e M e a s u r e t h e
p r e s s u r e g a u g e
CDI ignition is
compression pressure
faulty
① Check the external joints for any leakage
② Check the air is distributed at correct time
③ Check if the valve clearance is too small
④ Check the sealing between valve and the
valve seat
⑤ Check if the piston ring is broken or stuck
in the ring groove or lack of elasticity
⑥ Check the piston ring and cylinder for any
abrasion
Continue to work after start-up
Use the diagnostic tool to check
yes
Check the ignition system
yes
No
A f t e r t h e i n j e c t o r i s
u n p l u g g e d, s t a r t t h e
ignition to see if the fuel
is atomized.
yes
yes
Insufficient
compression pressure
in cylinder
① Check the fuel tank cover
vent for any obstruction
② Check if the fuel filter is
clogged.
③ Check if the fuel nozzle
is blocked
④ Check if the fuel pipe is
broken
No
to check if
there is fuel in
the fuel tank
No
Fill with
gasoline
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