Cub Cadet ISeries - Manual (Page 134)

ELECTRICAL SYSTEM
128
NOTE: Usage of the DC Shunt tool is detailed in
the 1995 and 1999 editions of their Update Sem-
inar materials.
Kohler makes a proprietary Rectifier/Regulator
tester (Kohler Part Number 25 761 20 and the up-dated
version: 25 761 20-S). This tester works on Kohler reg-
ulator / rectifiers and the company claims it works on
similar systems from other companies.
See Figure 7.26.
• Instructions are included with the Kohler tool
(TT480-A)
Testing the charging system:
Quick and dirty test:
1. Check voltage across the battery posts using a
DMMDMM set to read D.C. voltage with the
engine turned-off. It will read battery voltage,
typically around 12 V.
2. Start the engine and repeat the voltage mea-
surement. The system voltage should rise,
reflecting the output of the charging system, typ-
ically in the range of 12.5 - 14.5 V.
NOTE: If the voltage does not rise, or rises sig-
nificantly above this threshold, there is a prob-
lem with the charging system that needs to be
identified using more in-depth techniques.
NOTE: If system voltage is beyond roughly 15.7
volts, it is over charging and there is a problem
with the voltage regulator / rectifier.
To identify a specific charging system problem, iso-
late the components of the system and check their per-
formance individually.
1. First check the raw A.C. Voltage output from the
stator. It will be necessary to compare it to the
engine manufacturer’s specified output. This
varies from model to model. See Figure 7.27.
1a. With a DMM set to read A.C. Voltage, con-
nect the probes between ground and one of
the white wires from the stator.
1b. Leave the regulator-rectifier connected to
the harness.
1c. Start the engine and run it at 3,600 RPM.
1d. Read the voltage on the meter.
1e. If the voltage is substantially low, try the
other white wire.
2. If raw out-put of the running alternator is less
than the manufacturer’s specifications, check
the stator.
2a. With the engine stopped, unplug the stator
lead from the voltage regulator / rectifier.
Figure 7.26
Figure 7.27
Regulator / rectifier
+ probe to
white wire
Raw stator out-put
@3,600 RPM