260
Section 4 Engine Service
Engine Troubleshooting Chart
Cause Remedy
Engine lacks power
Choke partially closed. Open choke.
Improper carburetor adjustment. Adjust carburetor.
Magneto improperly timed. Time magneto.
Worn rings or piston. Replace rings or piston.
Air cleaner fouled. Clean air cleaner.
Lack of lubrication (four cycle only). Fill crankcase to the proper level.
Valves leaking (four cycle only). Grind valves and set to recommended specifi cations.
Reed fouled or sluggish (two cycle). Clean or replace reed.
Improper amount of oil in fuel mixture (two cycle only). Drain tank; fi ll with correct mixture.
Crankcase seals leak (two cycle only). Replace worn crankcase seals.
Engine overheats
Engine improperly timed. Time engine.
Carburetor improperly adjusted. Adjust carburetor.
Airfl ow obstructed. Remove any obstructions from air passages in shrouds.
Cooling fi ns clogged. Clean cooling fi ns.
Excessive load on the engine. Check operation of associated equipment; reduce
excessive load.
Carbon in combustion chamber. Remove cylinder head and clean carbon from head
and piston.
Lack of lubrication (four cycle only). Fill crankcase to proper level.
Improper amount of oil in fuel mixture (two cycle only). Drain tank; fi ll with correct mixture.
Engine surges or runs unevenly
Fuel tank cap vent hole clogged. Open vent hole.
Governor parts sticking or binding. Clean and, if necessary, repair governor parts.
Carburetor throttle linkage or throttle shaft and/or
butterfl y binding or sticking.
Clean, lubricate, or adjust linkage and deburr throttle
shaft or butterfl y.
Intermittent spark or 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 magneto. Check
wires for poor connections, cuts or breaks.
Improper carburetor adjustment. Adjust carburetor.
Dirty carburetor. Clean carburetor.
Engine vibrates excessively
Engine not securely mounted. Tighten loose mounting bolts.
Bent crankshaft. Replace crankshaft.
Associated equipment out of balance. Check associated equipment.
Figure 13-31.
Continued.
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