TROUBLESHOOTING
POOR PERFORMANCE AT LOW AND IDLE SPEED
1.
Spark Plug Inspection
Remove and inspect the spark
plug.
Is the spark plug in good condition?
NO - • Plug not serviced frequently enough
• Incorrect spark plug heat range
• Incorrect spark plug gap
YES - GO TO STEP 2.
2.
Ignition Timing Inspection
Check the ignition timing.
te the ignition timing within specification?
NO - • Faulty ECM
• Faulty ignition pulse generator
• Improper valve timing
YES - GO TO STEP 3.
3. Carburetor pilot screw Inspection
Check the carburetor pilot screw adjustment.
te the pilot screw in the correct position?
NO - page 5-18
YES - GO TO STEP 4.
4. Starting enrichment (SE) valve Inspection
Check the starting enrichment (SE) valve.
te the starting enrichment (SE) valve OK?
NO - Faulty starting enrichment (SE) valve
YES - GO TO STEP 5.
5. Intake Pipe Leaking Inspection
Check for leaks at the intake manifold boot.
Does it leak?
YES - • Loose intake manifold mounting bolt
• Damaged insulator
• Damaged O-ring
NO - GO TO STEP 6.
6. Spark Test
Perform spark test.
te the spark good ?
NO -
YES -
Faulty carbon or wet fouled spark plug
Faulty ECM
Faulty ignition coil
Broken or shorted spark plug wire
Faulty engine stop switch
Faulty ignition pulse generator
Faulty ignition switch
Loose or disconnected ignition system wires
Carburetor not serviced frequently enough
Improperly adjusted valve clearance
21-5
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