Onan MCCK - TROUBLE SHOOTING

POSSIBLE CAUSE
REMEDY
TROUBLE SHOOTING _
POSSIBLE CAUSE
REMED Y
ENGINE WILL NOT START WHEN CRANKED
Lack of fuel or faulty
carburetion.
Clogged fuel screen.
Refill tank. Check fuel
system. Clean, adjust
as necessary.
Clean.
ENGINE WILL
Battery discharged.
Loose connections.
Defective starting circuit.
Defective switch.
Oil too light or diluted.
Engine misfiring.
Faulty ignition.
Too much oil.
NOT CRANK
Recharge.
Tighten connections.
Repair or replace as
necessary.
Replace.
Drain; refill with correct
oil.
Clean; adjust or replace
spark plugs.
Clean, adjust, or replace
spark plugs.
Drain excess oil.
Cylinders flooded.
Poor fuel.
Poor compression.
Wrong breaker point gap.
ENGINE MISFIRES
Spark plug gap too narrow.
Intake air leak.
Faulty ignition.
Low compression.
Crahk few times with
spark plugs removed.
Drain; fill with fresh fuel.
Tighten spark plugs.
Reset breaker points.
AT LIGHT LOAD
Adjust to correct gap.
Tighten or replace mani¬
fold and carburetor gaskets.
Clean; adjust or replace
spark plugs.
Tighten cylinder head and
spark plugs.
ENGINE MISFIRES UNDER HEAVY LOAD
Spark plug gap too wide. Adjust gap.
Faulty ignition. Clean; adjust or replace
spark plugs.
ENGINE CRANKS TOO STIFFLY
Tooheavyoilincrankcase. Drain; refill with lighter
oil.
EXCESSIVE OIL CONSUMPTION, LIGHT BLUE
SMOKY EXHAUST
Oil leaks from oil base or
connections. This does
not cause smoky exhaust.
Replace gaskets. Tighten
screws and connection.
Check breather valve.
BLACK. SMOKY EXHAUST, EXCESSIVE FUEL CON¬
SUMPTION. FOULING OF SPARK PLUG WITH SOOT,
POSSIBLE LACK OF POWER UNDER HEAVY LOAD
Fuel mixture too rich. Adjust carburetor or choke.
Install needed carburetor
parts.
Choke not open. Inspect linkage and setting.
Clogged carburetor. Clean jet and adjust carb.
Clogged fuel screen. Clean
ENGINE BACKFIRES
Lean fuel mixture. Clean or adjust carburetor.
Poor fuel. Refill with good, fresh
fuel.
Dirty air cleaner. Clean.
Lack of crankcase vacuum . Clean breather valve.
ENGINE RACES
Governor not controlling Check governor perfor-
carburetor. mance&linkage condition.
ENGINE STOPS
Fuel tank empty.
Defective ignition.
UNEXPECTEDLY
Fill with fresh fuel.
Check ignition system.
LOW 0
Defective gauge.
Oil too light or diluted
from leaking fuel pump
diaphragm.
PRESSURE
Replace.
Drain. Refill with proper
oil. Repair or replace fuel
pump.
SHARP METALLIC THUD. ESPECIALLY WHEN COLD
ENGINE FIRST STARTED
Low oil supply. Add oil.
Oil too low.
Sludge on oil cup screen.
Add oil.
Clean screen & oil sump.
Oil badly diluted. Change oil.
Badly worn oil pump.
Replace.
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