Kohler Aegis ELH775 Service Manual page 60

Electrical System
Test for Spark
NOTE: If 2 ignition system 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 coil 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
1 cylinder is not fi ring or 1
cylinder has good spark
and other cylinder has no or
intermittent spark.
Tester shows spark but engine
misses or won't run on that
cylinder.
Neither side is fi ring.
Both cylinders have good
spark but engine runs poorly
or existing plug condition is
questionable.
60
Possible Cause
Wiring, Connections, or
System Power
Spark Plug(s)
Flywheel Key
Ignition Switch, EFI
System, Kill Lead
Spark Plug(s)
Flywheel Key
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Conclusion
Using a DVOM, attach black (-) lead of meter to battery
ground, remove primary plug from coil, test voltage at
red wire with black tracer at coil primary connector with
ignition key ON. Battery voltage should be seen. If no
voltage, check all fuses. Key OFF, perform continuity
test between black primary wire connector and
corresponding terminal connector (ignition coil #1 or
#2) on black or grey ECU connector (see EFI System
Wiring Diagram). If no continuity is found, repair or
replace electrical wiring harness. If continuity is found,
refer to EFI System, Ignition Coil Testing or exchange
ignition coils (side to side) and retest. If problem follows
ignition coil, replace that coil. If problem stays with
cylinder, test circuit (power and ground) for problem
cylinder. Repair/replace as needed. Test ignition coils
and connections. Refer to Test Ignition System (on
previous page).
Try new spark plug(s).
Remove fl ywheel, inspect key, replace key if damaged.
Test for "Safety System Active" as described in step 1
of Test Ignition System (on previous page). Inspect
red 10 amp fuses. Replace fuse if found blown. If fuse
is OK, using a DVOM, attach black (-) lead of meter to
battery ground, key ON, test for voltage at 3 red 10
amp fuses. Battery voltage should be seen on both
sides of fuses. If voltage is found on 1 side of fuse only,
inspect for blown fuse or inspect fuse holder/terminals
for arcing or corrosion. If no voltage is seen at any fuse,
further electrical testing inspection is required
(application, key switch, ground connections, etc.)
Recheck position of ignition switch and check for
shorted kill lead.
Install new spark plug(s) and retest engine
performance.
Remove fl ywheel, inspect key, replace key if damaged.
66 690 14 Rev. A