SYM
1. GENERAL INFORMATION/TROUBLE DIAGNOSIS
1-13
B. Engine run sluggish (Speed does not pick up, lack of power)
Check and adjustment
Fault condition
Probable causes
Try gradual acceleration
and check engine speed
Engine speed can be
increased.
Engine speed can not be
increased.
Check ignition timing
(Using ignition lamp)
Check cylinder compression
pressure (using compression
pressure gauge)
Ignition timing correct
Incorrect ignition timing
Compression pressure correct
No compression
Check if carburetor jet is
clogged
No clogged
Clogged
Remove spark plug
Check if engine over heat
No foul or discoloration
Fouled and discoloration
No knock
Knock
1. Air cleaner clogged
2. Poor fuel supply
3. Lines in fuel tank evaporation
system clogged
4. Exhaust pipe clogged
5. Fuel level too low in carburetor
6. Fuel nozzle clogged in
carburetor
1. Malfunction of CDI
2. Malfunction of AC alternator
1. Cylinder & piston ring worn out
2. Cylinder gasket leaked
3. Sand hole in compression parts
4. Valve deterioration
5. Seized piston ring
1. Remove foreign
1. Remove dirt
2. Incorrect spark plug heat range
1. Piston and cylinder worn out
2. Lean mixture
3. Poor fuel quality
4. Too much carbon deposited in
combustion chamber
5. Ignition timing too advanced
6. Poor circuit on the cooling
system
Normal
Engine overheat
Continually drive in
acceleration or high speed
1. Too much carbon deposited in
combustion chamber
2. Lean mixture
3. Poor fuel quality
4. Ignition timing too advanced
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