Sym ATTILA RS-21 EFi 150 Service Manual page 18

B. Engine run sluggish (Speed does not pick up, lack of power)
Check and adjustment
Try gradual acceleration
and check engine speed
Engine speed can be
increased.
Check ignition timing
(Using ignition lamp)
Ignition timing correct
Check cylinder
compression pressure
(using compression
pressure gauge)
Compression pressure
correct
Check if fuel injector is
clogged
No clogged
Remove spark plug
No foul or discoloration
Check if engine over heat
Normal
Continually drive in
acceleration or high
speed
No knock
This chapter Contents
1. General Information/Trouble Diagnosis
Fault condition
Engine speed can not
be increased.
Incorrect ignition timing
No compression
pressure
Clogged
Fouled and discoloration
Engine overheat
Knock
Probable causes
1. Air cleaner clogged
2. Poor fuel supply
3. Lines in fuel tank evaporation system
clogged
4. Exhaust pipe clogged
5. Fuel injector clogged
1. Malfunction of ECU
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. Replace fuel injector
1. Remove dirt
2. Incorrect spark plug heat range
1. Piston and cylinder worn out
2. Injector clogged
3. Poor fuel quality
4. Too much carbon deposited in
combustion chamber
5. Ignition timing too advanced
1. Too much carbon deposited in
combustion chamber
2. Malfunction of fuel injector
3. Poor fuel quality
4. Ignition timing too advanced
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