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Electrical System
66 690 14 Rev. A
KohlerEngines.com
Carbon Fouled
Soft, sooty, black deposits indicate incomplete
combustion caused by a restricted air cleaner, over rich
fuel mixture, weak ignition, or poor compression.
Troubleshooting Guide
Test Ignition System
NOTE: If engine starts or runs during testing, you may need to ground kill lead to shut it down. Because you have
interrupted kill circuit, it may not stop using switch.
Isolate and verify trouble is within engine.
1. If Kohler diagnostic software is available, review "Safety System Active" status in Data Display screen. If yes is
displayed, equipment safety circuit is active (seat switch/PTO switch/Safety interlocks, etc.). This must be
corrected prior to continuing testing.
If diagnostic software is not available, locate connectors where wiring harnesses from engine and equipment are
joined. Separate connectors and remove white kill lead from engine connector. Rejoin connectors and position or
insulate kill lead terminal so it cannot touch ground. Try to start engine to verify whether reported problem is still
present.
Condition
Possible Cause
Conclusion
Problem goes away.
Electrical System
Check key switch, wires, connections,
safety interlocks, etc.
Problem persists.
Ignition or Electrical System
Leave kill lead isolated until all testing
is completed.
Identify white kill lead of engine
wiring harness connector. Establish
a connection to a known good
ground location. Engine should kill
completely. If not or only 1 cylinder is
a
ff
ected, test ignition coils.
Overheated
Chalky, white deposits indicate very high combustion
temperatures. This condition is usually accompanied
by excessive gap erosion. Lean fuel mixture settings,
an intake air leak, or incorrect spark timing are normal
causes for high combustion temperatures.
