Troubleshooting Guide - Kohler CH940-CH1000 Service Manual

Electrical System

Troubleshooting Guide

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.
15/20/25 Amp Battery Charging Systems
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.
Problem
*NOTE: Turn on lights, if 60 watts or more. Or
1. Trace B+ lead from rectifi er-regulator to key
switch, or other accessible connection.
Disconnect it from switch or connection.
Connect an ammeter from loose end of B+
lead to positive terminal of battery. Connect
DC voltmeter from loose end of B+ lead to
negative terminal of battery. With engine
running at 3600 RPM, read voltage on
voltmeter.
If voltage is 13.8 volts or more, place a
minimum load of 5 amps* on battery to
reduce voltage. Observe ammeter.
2. Remove connector from rectifi er-regulator.
No Charge
With engine running at 3600 RPM, measure
to Battery
AC voltage across stator leads using an AC
voltmeter.
3 a. With engine stopped, measure
b. With engine stopped, measure
4. Perform same test as Step 1 above.
Battery
Continuously
Charges at
High Rate
42
Test
place a 2.5 ohm, 100 watt resistor
across battery terminals.
resistance across stator leads using an
ohmmeter.
resistance from each stator lead to
ground using an ohmmeter.
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Conclusion
1. If voltage is 13.8-14.7 and charge rate
increases when load is applied, charging
system is OK and battery was fully charged.
If voltage is less than 13.8 or charge rate
does not increase when load is applied,
check regulator-rectifi er ground. Adequate
ground is required for regulator-rectifi er to
operate. If ground path is good, test stator
(tests 2 and 3).
2. If voltage is 28 volts or more, stator is OK.
Rectifi er-regulator is faulty. Replace
rectifi er-regulator.
If voltage is less than 28 volts, stator is
probably faulty and should be replaced. Test
stator further using an ohmmeter (test 3).
3 a. If resistance is 0.064/0.2 ohms, stator is
OK.
If resistance is infi nity ohms, stator is
open. Replace stator.
b. If resistance is infi nity ohms (no
continuity), stator is OK (not shorted to
ground).
If resistance (or continuity) is measured,
stator leads are shorted to ground.
Replace stator.
4. If voltage is 14.7 volts or less charging
system is OK. Battery is unable to hold a
charge. Service battery or replace as
necessary.
If voltage is more than 14.7 volts, rectifi er-
regulator is faulty. Replace rectifi er-
regulator.
62 690 01 Rev. C