Kohler Command CH620 Service Manual page 71

Condition
Both cylinders have good spark but
engine runs poorly or existing plug
condition is questionable.
1 cylinder has good spark and other
cylinder has no or intermittent spark.
Spark on both cylinders but power is
suspect.
Test Ignition Systems
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. 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
Problem goes away.
Problem persists.
Test DSAI Ignition Modules and Connections
1. Remove blower housing from engine. Inspect wiring for any damage, cuts, bad crimps, loose terminals, or broken
wires. Check that connections are oriented properly on terminals of modules.
2. Disconnect leads from ignition module(s) and clean all of terminals (male and female) with aerosol electrical
contact cleaner to remove any old dielectric compound, dark residue, dirt, or contamination. Disconnect spark
plug leads from spark plugs.
3. Using a multi-meter, check that a proper ground is established between ground (black) lead of DSAI module
(closest to spark plug lead) and a known good ground location on engine.
4. Turn key switch to ON position and check for 12 volts at center/power (red) lead terminal of DSAI module. Use
same ground location for multi-meter as in checking for timing advance.
Condition
All tests are OK but module has no
spark or fails to advance.
Any test is BAD.
24 690 06 Rev. O
Possible Cause
Spark Plug(s)
Ignition
Sheared Flywheel Key
Possible Cause
Electrical System
Ignition or Electrical System
Possible Cause
Ignition Module
Ignition Module or Connections
KohlerEngines.com
Electrical System
Conclusion
Install new spark plug(s) and retest
engine performance.
If problem persists, check for??
Test ignition modules and
connections.
Check for broken key.
Conclusion
Check key switch, wires, connections,
safety interlocks, etc.
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 one cylinder
is aff ected, test ignition modules and
white kill lead connection.
Conclusion
Replace aff ected module.
Determine cause and fi x as required;
retest.
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