695578
13-2
Governor parts sticking or binding.
Clean, and if necessary repair governor parts.
Carburetor throttle linkage or throttle
Clean, lubricate, or adjust linkage and deburr throttle shaft or butterfly.
shaft and/or butterfly binding or sticking. Carburetor throttle linkage or throttle
Intermittent spark at spark plug.
Disconnect ignition cut-off wire at the engine. Crank engine. If spark,
check ignition switch, safety switch and interlock switch. If no spark,
check ignition air gap. Check wires for poor connections, cuts or breaks.
Governor not set properly.
Perform static governor setting.
Dirty carburetor.
Clean carburetor.
Valves not seated.
Clean carbon from valve, recut seats, check valve clearance.
Spark plug fouled.
Replace spark plug.
Improper spark plug gap.
Regap spark plug.
Spark plug porcelain cracked.
Replace spark plug.
Improper valve clearance.
Adjust valve clearance to recommended specifications.
Weak valve spring.
Replace valve spring.
Air cleaner fouled.
Service air cleaner.
Remedy and Reference
Cause
Engine Misses Under Load
Table 1. 4-Cycle Engine Troubleshooting Chart (Continued)
Engine Lacks Power
Engine Overheats
Engine Surges or Runs Unevenly
Engine Vibrates Excessively
Engine not securely mounted.
Tighten loose mounting bolts.
Bent crankshaft.
Replace crankshaft.
Associated equipment out of balance.
Check associated equipment.
Air cleaner fouled.
Service air cleaner.
Lack of lubrication.
Fill crankcase to the proper level.
Ignition improperly timed.
Replace flywheel key.
Valves leaking.
Grind valves and set to recommended specifications.
Worn rings.
Replace rings.
Cooling fins clogged.
Clean cooling fins.
Air flow obstructed.
Remove any obstructions from air passages in shrouds.
Fuel tank cap vent hole clogged.
Open vent hole.
Lack of lubrication.
Fill crankcase to proper level.
Excessive load on engine.
Check operation of associated equipment. Reduce excessive load.
Carbon in combustion chamber.
Remove cylinder head and clean carbon from head and piston.
Engine improperly timed.
Replace flywheel key if sheared.