Part III Fault Judgement and Repair
10
Part III Fault Judgement and Repair
3-1 Fault judgement
3-1-1 Start difficulty
Phenomenon
Cause
Remedy
Normal cylinder
compression
Normal
spark of
spark
plug
Abnormal
fuel
system
Impeded
fuel flow or
no fuel flow
No fuel in fuel tank
Refuel
Clogged venthole of fuel
tank cap
Dredge
Main measuring hole is
improperly adjusted or
blocked
Re-adjust or clean, blow through
Float needle hole is
blocked
Remove needle valve for repairing,
cleaning and blowing through
The float is stuck or
damaged
Repair the float
Unobstructe
d fuel flow
Fuel is too dirty or
deteriorated
Replace fuel
There is water in fuel
Replace fuel
There is excessive fuel in
the cylinder
Drain the fuel, and wipe and dry spark
plug electrode
Fuel label is incorrect
Use according to specified label
Normal
fuel
supply
system
Spark of
HV wire
is normal
Spark plug
is poor
Electrode is dirty with
carbon deposit
Remove the dirt and carbon deposit
Insulator is damaged,
electrode is severe ablated
Replace the spark plug
Electrode clearance is
incorrect
Adjust electrode clearance
HV wire
has no
spark
Spark plug
is normal
HV wire is damaged
Replace the HV wire
Ignition coil is damaged
Replace the ignition coil
Magnet is demagnetized
Replace the flywheel
The clearance between
ignition coil and flywheel
is abnormal
Adjust the clearance between ignition coil
and flywheel
Phenomenon
Cause
Remedy
Cylinder
compression is
poor
Normal fuel supply
system
The ignition
system is
normal
Piston ring wear exceeds
the limit
Replace it with complete set of new ring
Piston ring is broken
Replace it with complete set of new ring
Piston ring is stuck
Clear carbon deposit
The spark plug is not
provided with sealing
gasket or is not tightened
Mount the gasket and tighten it
Air leakage of joint face
between the cylinder body
and the cylinder cover
Check the flatness of joint face of cylinder
pad and cylinder body and cylinder cover
And tighten cylinder cover bolts
according to specified torque and
sequence
Valve leakage
Check valve clearance and valve
tightness, repair when necessary
