Troubleshooting – John Deere stx38 User Manual
Page 42
3 - 10
4/23/97
TROUBLESHOOTING
ENGINE
TROUBLESHOOTING
Problem or
Symptom
Engine cranks but will not
start or starts hard
Engine will not stay running or
runs rough
Engine stalls frequently
Engine backfires
Engine surges, uneven or
uncontrolled rpm
Engine misses
Low power under load
Engine has no spark
Engine will not crank
Exhaust black, engine
floods or burns rich
Exhaust smoke blue or high
oil consumption
Engine has low oil pressure
Fuel in oil
Engine overheats
Excessive engine noise or
vibration start or starts hard
Check or
Solution
Spark plug fouled or
incorrect gap. Incorrect
spark plug.
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Defective ignition
compon
ents.
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Starter worn. Cranking
rpm too slow, cables
corroded, battery weak.
Engine overloaded.
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Fuel tank outlet
restricted, shut-off valve
not fully open, fuel filter
or line restricted. Fuel
stale, contains water, or
wrong type.
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Air filter element plugged
or oil soaked.
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Choke, throttle, or
governor linkage worn or
out of adjusted.
Carburetor set too rich.
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Carburetor worn,
contaminated with
debris or varnish.
Passages plugged.
Wrong jets or adjusted
too lean.
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Carburetor, intake
manifold, or cylinder
head gaskets leaking.
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Low compression: worn
piston, rings, cylinder,
valves. Warped head.
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Valve clearance
incorrect. Burned or
warped valves and seats.
Defective springs.
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