Sym MAXSYM 400i Service Manual page 18

B. Engine runs sluggish (Speed
does not pick up, lack of power)
Check and adjustment
Accelerate gradually and
check engine RPM
Engine RPM can be
increased
Check ignition timing
(Using ignition lamp)
Correct ignition timing
Check cylinder
compression pressure
(using compression
Normal compression pressure
Check if the fuel
injector is clogged or
Not clogged
Remove and check the
spark plug
No contamination or
discoloration
Check if the engine is
over heated
Normal
Continually drive in
acceleration or high
speed
No knocking
To this chapter contents
Fault condition
Engine RPM cannot be
increased
Incorrect ignition
timing
Abnormal compression
pressure
Clogged
Contaminated or
Engine overheated
Knocking
1. General Information
Probable causes
1. Clogged air cleaner
2. Poor fuel supply
3. Clogged exhaust pipe
4. Clogged fuel injector
1. Malfunction of ECU
2. Malfunction of AC Generator
1. Worn out cylinder or piston ring
2. Cylinder gasket leakage
3. Sand hole in compression parts
4. Valve deterioration
5. Jammed piston ring
1. Replace the fuel injector
1. Remove the dirt
2. Incorrect spark plug heat range
1. Worn out piston or cylinder
2. Abnormal fuel injector
3. Poor fuel quality
4. Carbon deposit in the combustion
chamber
1. Carbon deposit in the combustion
chamber
2. Malfunction of fuel injector
3. Poor fuel quality
4. Abnormal ignition timing
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