Section 03
ENGINE
Subsection 02
(TROUBLESHOOTING)
VMR2004_125_03_02A.FM
03-02-15
ENGINE GENERAL
SYMPTOM
ENGINE BACKFIRES.
CONDITION
NORMAL USE.
Test/Inspection
1. Check spark plug and/or electrical system.
a. Carbon accumulation caused by defective spark plug.
Clean carbon accumulation and replace spark plug.
b. Electrical system has failure.
Replace defective part(s).
2. Check leakage on intake manifold.
a. Air leak on intake system.
Retighten screws and/or replace intake manifold.
3. Check exhaust air leaking.
a. Exhaust gasket is leaking.
Retighten screws and/or replace exhaust gasket.
4. Check intake valve(s) for leaking.
a. Intake valve(s) is (are) leaking.
Repair or replace valve(s).
5. Check if fuel supply is insufficient at high RPM.
a. Fuel line is contaminated and/or bent (engine gets lean).
Clean and/or replace defective part(s).
6. Check carburation.
a. Faulty carburetor settings.
Adjust carburetor.
SYMPTOM
ENGINE SUDDENLY TURNS OFF.
CONDITION
NORMAL USE.
Test/Inspection
1. Check spark plug cap contact and/or cable.
a. Spark plug cap loose.
Replug cap.
b. Spark plug cable melted and/or damaged.
Replace spark plug cable.
2. Check condition of spark plug (blue spark ideal).
a. Red, jumping spark means a damaged spark plug.
Replace spark plug with appropriate heat range (refer to TECHNICAL DATA).
b. Condition of spark plug.
Readjust carburator and/or replace spark plug.
