Kohler Aegis LH775 Service Manual page 50

Electrical System
Troubleshooting Guide
25 Amp Battery Charging System
NOTE: Always zero ohmmeter on each scale before testing to ensure accurate readings. Voltage tests should be
made with engine running at 3600 RPM - no load. Battery must be good and fully charged.
When problems occur in keeping battery charged or battery charges at too high a rate, problem can usually be found
somewhere in charging system or with battery.
To test charging system for no charge to battery:
1. Insert an ammeter in B+ lead from rectifi er-regulator.
With engine running at 3600 RPM and B+ (at
terminal on rectifi er-regulator) to ground using a DC
voltmeter.
If voltage is 13.8 volts or more, place a minimum
load of 5 amps (turn on lights if 60 watts or more, or
place a 2.5 ohm, 100 watt resistor across battery
terminals) on battery to reduce voltage. Observe
ammeter.
Condition
Charge rate increases
when load is applied.
Charge rate does not
increase when load is
applied.
2. Remove connector from rectifi er-regulator. With
engine running at 3600 RPM, measure AC voltage
across stator leads using an AC voltmeter.
Condition
Voltage is 28 volts or
more.
Voltage is less than 28
volts.
3. With engine stopped, measure resistance across
stator leads using an ohmmeter.
Condition
Resistance is 0.1/0.2
ohms.
Resistance is 0 ohms.
Resistance is infi nity
ohms.
4. With engine stopped, measure resistance from each
stator lead to ground using an ohmmeter.
Condition
Resistance is infi nity ohms
(no continuity).
Resistance (or continuity)
measured.
50
Conclusion
Charging system is OK
and battery was fully
charged.
Test stator and rectifi er-
regulator (steps 2 and 3).
Conclusion
Stator is OK. Rectifi er-
regulator is faulty; replace.
Stator is faulty; replace.
Test stator further using an
ohmmeter (steps 3 and 4).
Conclusion
Stator is OK.
Stator is shorted; replace.
Stator is open; replace.
Conclusion
Stator is OK (not shorted
to ground).
Stator leads are shorted to
ground; replace.
KohlerEngines.com
To test charging system for battery continuously charging
at high rate:
1. With engine running at 3600 RPM, measure voltage
from B+ lead to ground using a DC voltmeter.
Condition
Voltage is 14.7 volts or
less.
Voltage is more than 14.7
volts.
FUSES
This engine has three (3) blade type automotive fuses.
Replacement fuses must have same rating as blown
fuse. Use fuse chart below to determine correct fuse.
Wire Color
2 Purple Wires
1 Red Wire w/ Black Stripe
1 Red Wire w/ White Stripe
2 Red Wires
Fuse Replacement
1. Shut engine off and remove key.
2. Locate fuse holders.
3. Remove fuse cover and pull out fuse.
4. Inspect fuse for a solid fusible link or a broken
fusible link. Replace fuse if fusible link is broken. If
you are not sure if fusible link is broken, replace
fuse.
5. Insert fuse into fuse holder until it is seated properly.
Install fuse cover.
Conclusion
Charging system is OK.
Battery is unable to hold
charge; service or replace.
Faulty rectifi er-regulator;
replace.
Fuse Rating
30-amp Fuse
10-amp Fuse
10-amp Fuse
66 690 07 Rev. --