Yamaha E40X Owner's Manual page 173

Trouble
C. Engine idles
irregularly
or stalls
Possible Cause
1. Spark plug(s) fouled or wrong type
2. Fuel system obstructed
3. Fuel contaminated or stale
4. Fuel filter clogged
5. Failed ignition parts
6. Warning system activated
7. Spark plug gap incorrect
8. Poor connections or damaged
ignition wiring
9. Specified engine oil not used
10. Thermostat faulty or clogged
11. Carburetor adjustments incorrect
12. Fuel pump damaged
13. Air vent screw on the fuel tank is
closed
14. Choke knob is pulled out
15. Motor angle is too high
16. Carburetor is clogged
17. Fuel joint connection is wrong
18. Throttle valve adjusts incorrect
19. Battery lead is removed
1. Inspect spark plug(s). Clean or
replace with recommended type.
2. Check for pinched or kinked fuel
line or other obstructions in fuel
system.
3. Fill tank with clean, fresh fuel.
4. Clean or replace filter.
5. Have Yamaha dealer service.
6. Find and correct cause.
7. Inspect and adjust as specified.
8. Check wires for wear or breaks.
Tighten all loose connections.
9. Check and replace it as specified.
10. Have Yamaha dealer service.
11. Have Yamaha dealer service.
12. Have Yamaha dealer service.
13. Open the air vent screw.
14. Return to home position.
15. Return to normal operating
position.
16. Have Yamaha dealer service.
17. Connect correctly.
18. Have Yamaha dealer service.
19. Connect securely.
5-2
GB
Remedy