Section 03 TROUBLESHOOTING
Subsection 01 (TROUBLESHOOTING CHART)
SMR2000-042-03-01.FM 03-01-5
ENGINE CONTINUALLY BACKFIRES
ENGINE DETONATION OR PINGING
OTHER OBSERVATION POSSIBLE CAUSE REMEDY
Weak spark
• Fouled, defective spark plugs
(carburetor models)
• Clean/replace
• Malfunction of rev limiter in MPEM
(carburetor models)
• Clean/replace, refer to section ELEC-
TRICAL SYSTEM
Spark plugs • Spark plug leads or wiring reversed • Check with wiring diagram
Ignition timing/TDC setting
• Incorrect setting • Check/reset, refer to section ELECTRI-
CAL SYSTEM
• Sheared flywheel key • Check/replace, refer to sections ELEC-
TRICAL SYSTEM and ENGINE
Carburetor
(if so equipped)
• Carburetion too lean • Check/adjust, refer to section FUEL
SYSTEM
Engine
• Intake leak/crankshaft seal failure
(carburetor models)
• Pressure check engine, refer to section
ENGINE
OTHER OBSERVATION POSSIBLE CAUSE REMEDY
Ignition
• Timing too far advanced • Check/reset
• Spark plug heat range too high • Check/change to correct range
• Defective MPEM (carburetor models) • Check/replace, refer to section ELEC-
TRICAL SYSTEM
Engine temperature
• Engine overheats • Check, see engine overheats
• Fuel octane too low of poor quality • Use good quality fuel
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