Kohler Command PRO CH620-CH740 Owner's Manual page 50

Electrical System
Test for Spark
NOTE: If 2 testers are available, testing can be performed simultaneously for both cylinders. However, if only 1 tester
is available, 2 individual tests must be performed. Side not being tested must have spark plug lead connected
or grounded. Do not crank engine or perform tests with 1 spark plug lead disconnected and not grounded, or
permanent system damage may occur.
1. With engine stopped, disconnect 1 spark plug lead. Connect spark plug lead to post terminal of spark tester and
attach tester clip to a good engine ground.
2. Crank engine over, establishing a minimum of 550-600 RPM, and observe tester(s) for spark.
3. Repeat spark test on opposite cylinder if cylinders are being tested individually.
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 Timing Advance (DSAI and Smart-Spark
1. Make a line near edge of fl ywheel screen with a marking pen, chalk, or narrow tape.
2. Connect an automotive timing light to cylinder that had good spark.
3. Run engine at idle and use timing light beam to locate line on screen. Draw a line on blower housing next to line
on screen. Accelerate to full throttle and watch for movement of line on screen relative to line on blower housing.
If both cylinders had good spark, repeat test on other cylinder.
Condition
Line on screen did not move away
from line on blower housing during
acceleration.
Lines made on blower housing not
90° apart.
Test Ignition Modules and Connections (DSAI only)
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.
42
Possible Cause
Spark Plug(s)
Ignition
Timing Advance
only)
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Possible Cause
Ignition
Possible Cause
Ignition Module
Ignition Module or Connections
KohlerEngines.com
Conclusion
Install new spark plug(s) and retest
engine performance.
If problem persists, check for timing
advance (DSAI and Smart-Spark
only).
Test ignition modules and
connections (DSAI and Smart-Spark
only).
Check for timing advance (DSAI and
Smart-Spark only).
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Conclusion
Test ignition modules and
connections.
Conclusion
Replace affected module.
Determine cause and fi x as required;
retest.
24 690 06 Rev. K
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