Troubleshooting - KYMCO MXU400 Service Manual

Troubleshooting

Problem: Starting impaired
Condition
1. Starter jet obstructed
2. Starter jet passage obstructed
3. Carburetor leaking air
4. Gas contaminated
Problem: Idling or low speed impaired
Condition
1. Slow jet obstructed - loose
2. Slow jet outlet obstructed
3. Low speed fuel screw setting incorrect
4. Float height incorrect
5. TPS out of adjustment
Problem: Medium or high speed impaired
Condition
1. High RPM "cut out" against RPM limiter
2. Main jet obstructed
3. Needle jet obstructed
4. Vacuum piston not operating properly
5. Filter obstructed
6. Float height incorrect
Problem: Overflow and fuel level fluctuations
Condition
1. Float valve worn - damaged
2. Float valve spring broken
3. Float not working properly
4. Float valve dirty
5. Float height too high - too low
4-12
Remedy
1. Clean jet
2. Clean passage
3. Replace gasket
4. Drain gas tank and fill with clean gas
Remedy
1. Clean - tighten jet
2. Clean outlet
3. Adjust screw
4. Adjust float height
5. Adjust TPS
Remedy
1. Shift into higher gear - decrease RPM speed
2. Clean main jet
3. Clean needle jet
4. Check piston operation
5. Clean filter
6. Adjust float height
Remedy
1. Replace valve
2. Replace spring
3. Adjust float height - replace float
4. Clean valve
5. Adjust float height