Suzuki FU150SC Manual page 90

7-1 SERVICING INFORMATION
TROUBLESHOOTING
ENGINE
Engine will not start,
or is hard to start.
Compression too low
1, Out of adjustment tappet clearance.
2. Worn valve guides or poor seating of valves.
3. Mistiming valves. :
4, Excessively worn piston rings.
5. Worn-down cylinder bore.
6. Poor seating of spark plug.
Plugs not sparking
1. Fouled spark plug.
2, Wet spark plug.
3. Defective ignition coil.
4, Open or short in high-tension cord.
§. Defective pick-up coil or CDI unit.
No fuel reaching the carburetor
1. Clogged fuel tank air vent pipe. -
2. Clogged or defective fuel valve.
3. Defective carburetor needle valve.
4. Clogged fuel hose, fuel filter or vacuum hose.
Adjust.
Repair or replace.
Adjust.
Replace.
Replace or rebore.
Retighten.
Clean.
Clean and dry.
Replace.
Replace.
Replace.
Clean.
Clean or replace.
Replace.
Clean or replace.
3. Not working tension adjuster.
Noise seems to come from clutch
1. Worn splines of countershaft or hub.
2. Worn teeth of clutch plates.
3. Distorted clutch plates, driven and drive.
4. Worn clutch release bearing.
5. Weakened clutch dampers.
6. Weakened clutch springs.
Engine stalls easily. 1. Fouled spark plug. Clean.
2. Defective pick-up coil or CDI unit. Replace.
3, Clogged fuel hose. . Clean.
4. Clogged jets in carburetor. Clean.
5. Out of adjustment tappet clearance. Adjust.
Noisy engine. Excessive valve chatter
-1: Too large tappet clearance. Adjust.
2. Weakened or broken valve springs. Replace.
3. Worn cam surface. Replace.
4. Worn and burnt camshaft journal. Replace.
Noise seems to come from piston
1. Worn down piston or cylinder. Replace.
2. Fouled with carbon combustion chamber. Clean.
3. Worn piston pin or piston pin bore. Replace.
4. Worn piston rings or ring grooves. Replace.
Noise seems to come from timing chain
1. Stretched chain. Replace.
2. Worn sprockets. Replace.
Repair or replace.
Replace.
Replace.
Replace.
Replace.
Replace the primary Driven gear.
Replace.
SERVICING INFORMATION 7-2