5-2EC. Engine idlesirregularly or stalls.1. Spark plug(s) fouled or incorrect type. 1. Inspect spark plug(s). Clean or replacewith recommended type.2. Fuel system obstructed. 2. Check for pinched or kinked fuel line orother obstructions in fuel system.3. Fuel contaminated or stale. 3. Fill tank with clean, fresh fuel.4. Fuel filter clogged. 4. Clean or replace filter.5. Failed ignition parts. 5. Have serviced by a Yamaha dealer.6. Warning system activated. 6. Find and correct cause of warning.7. Spark plug gap incorrect. 7. Inspect and adjust as specified.8. Poor connections or damaged ignitionwiring.8. Check wires for wear or breaks.Tighten all loose connections.Replace worn or broken wires.9. Specified engine oil not used. 9. Check and replace oil as specified.10. Thermostat faulty or clogged. 10. Have serviced by a Yamaha dealer.11. Carburetor adjustments incorrect. 11. Have serviced by a Yamaha dealer.12. Fuel pump damaged. 12. Have serviced by a Yamaha dealer.13. Air vent screw on the fuel tank closed. 13. Open the air vent screw.14. Choke knob pulled out. 14. Return to home position.15. Motor angle too high. 15. Return to normal operating position.16. Carburetor clogged. 16. Have serviced by a Yamaha dealer.17. Fuel joint connection incorrect. 17. Connect correctly.18. Throttle valve adjustment incorrect. 18. Have serviced by a Yamaha dealer.19. Battery lead disconnected. 19. Connect securely.D. Warning buzzersounds or indicatorlamp lights.1. Engine oil level low. 1. Fill oil tank with specified engine oil.2. Specified engine oil not used. 2. Check and replace oil with specifiedtype.3. Engine oil contaminated or deterio-rated.3. Replace oil with fresh, specified type.4. Oil filter clogged. 4. Have serviced by a Yamaha dealer.5. Oil feed/injection pump malfunctions. 5. Have serviced by a Yamaha dealer.Trouble Possible Cause Remedy