Sym VS150 - Page 128

3. GENERAL INFORMATION
C. Engine runs sluggish (especially in low speed and idling)
3-15
Check and adjustment Fault condition Probable causes
D. Engine runs sluggish (High speed)
Check ignition timing (using
ignition lamp)
Check for fuel supplying system
in automatic fuel cup
Check if carburetor clogged
1. Incorrect ignition timing
(malfunction of CDI or AC
alternator)
1. Rich mixture (loosen the screw)
2. Lean mixture (tighten the screw)
1. Poor heat insulation gasket
2. Carburetor lock loose
3. Poor intake gasket
4. Poor carburetor O-ring
5. Vacuum hose crack
1. Spark plug fouled
2. Malfunction of CDI
3. Malfunction of AC generator
4. Malfunction of ignition coil
5. Open or short circuit in spark plug
leads
6. Malfunction of main switch
1. Insufficient fuel in fuel tank
2. Fuel filter clogged
3. Restricted fuel tank vent
Good Abnormal
Good spark Poo
r
No air sucked Air sucked
Good Poo
r
Normal
Abnormal
Air sucked through carburetor
gasket
Adjust the air screw of
carburetor
No clogged Clogged
1. Cleaning
Remove spark plug, install
spark plug into spark plug cap
and perform spark test against
engine ground
Check and adjustment Fault condition
Probable causes
Check ignition timing
1. Malfunction of CDI
2. Malfunction of AC alternator
Normal Abnormal