Engine Service Manual

Electrical System
5732 690 03 Rev. I KohlerEngines.com
BATTERY CHARGING SYSTEM
NOTE: Observe following guidelines to avoid damage to electrical system and components:
● Make sure battery polarity is correct. A negative (–) ground system is used.
● Disconnect rectifi er-regulator plug and/or wiring harness plug before doing any electric welding on equipment
powered by engine. Disconnect all other electrical accessories in common ground with engine.
● Prevent stator (AC) leads from touching or shorting while engine is running. This could damage stator.
Most engines are equipped with a 12/15 amp regulated charging system. Some have a 25 amp regulated charging
system.
12/15/25 Amp Regulated Charging System
Stator
Stator is mounted on crankcase behind fl ywheel. Follow procedures in Disassembly and Reassembly if stator
replacement is necessary.
Rectifi er-Regulator
NOTE: When installing rectifi er-regulator, take note of terminal positions and install plug correctly.
NOTE: Disconnect all electrical connections attached to rectifi er-regulator. Testing may be performed with rectifi er-
regulator mounted or loose. Repeat applicable test procedure 2 or 3 times to determine condition of part.
Rectifi er-regulator is mounted on backing shroud assembly. To replace it, disconnect plug, remove mounting screws,
and ground lead.
Testing rectifi er-regulator may be performed as follows, using appropriate rectifi er-regulator tester.
To test 25 amp rectifi er-regulators:
1. Connect single lead adapter in between B+ (center)
terminal of rectifi er-regulator being tested and
squared single end of tandem adapter lead.
2. Connect tester ground lead (with spring clamp) to
body of rectifi er-regulator.
3. Connect red lead and 1 black lead to terminals on
open end of tandem adapter lead (connections are
not location specifi c).
4. Connect remaining black lead from tester to 1 outer
AC terminal on rectifi er-regulator.
5. Plug tester into proper AC outlet/power for tester
being used. Turn on power switch. POWER light
should be illuminated and 1 of 4 status lights may be
on as well. This does not represent condition of part.
6. Press TEST button until a click is heard and then
release. Momentarily 1 of 4 lights will illuminate
indicating partial condition of part.
To test 12/15 amp rectifi er-regulators:
1. Connect tester ground lead (with spring clamp) to
body of rectifi er-regulator being tested.
2. Connect tester red lead to B+ terminal of rectifi er-
regulator and 2 black tester leads to 2 AC terminals.
3. Plug tester into proper AC outlet/power for tester
being used. Turn on power switch. POWER light
should be illuminated and 1 of 4 status lights may be
on as well. This does not represent condition of part.
4. Press TEST button until a click is heard and then
release. Momentarily 1 of 4 status lights will
illuminate indicating condition of part.
Condition Conclusion
25 amp 12/15 amp
OK (green) light comes on and stays steady. Disconnect tester black lead
attached to 1 AC terminal and
reconnect it to other AC terminal.
Repeat test. If OK (green) light
comes on again, part is good
and may be used.
Part is good and may be used.
NOTE: A fl ashing LOW light can also occur as
a result of an inadequate ground lead
connection. Make certain connection
location is clean and clamp is secure.
Other lights come on.
Rectifi er-regulator is faulty and should not be used.