Governor System/Magnetic Pickup Operation Test - Kohler 8.5RES Service Manual

actuator (stepper motor) as the mounting holes
allow.
b. Refer to the Engine Service Manual for other
engine diagnostic and service information.
1
1. Electronic governor stepper motor
2. Carburetor throttle linkage
3. Carburetor mounting holes
Figure 5-12 Stepper Motor and Carburetor
5.8.4 Governor System/Magnetic
Pickup Operation Test
If the engine continues to operate erratically after the
previous checks, test the governor system operation
using the following procedure.
summarized in the flowchart in Figure 5-15.
Governor System Operation Test Procedure
1. Verify that the carburetor throttle linkage is
connected to the stepper motor as shown in
Figure 5-12.
2. Look for broken or loose wiring or plug connections
if the stepper motor moves erratically. Check the
condition of the throttle linkage, and verify that the
throttle plate closes completely.
3. Check the operation of the stepper motor at
startup.
a. If the throttle moves to the fully open throttle
position and then steps to and remains in the
fully closed position, the engine speed input is
probably missing. The engine starts and then
shuts down on an overspeed fault. Proceed to
step 4 to check the magnetic pickup.
b. If the throttle linkage moves erratically or not at
all at startup, proceed to step 7 to check the
stepper motor.
4. Verify the operation of the magnetic pickup by
connecting a voltmeter to the magnetic pickup
leads. See Figure 5-13.
48 Section 5 Component Testing and Adjustment
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3
TP5632721
The procedure is
If the air gap is correct, the voltage should be
1.75 volts AC minimum during engine cranking.
5. If the voltmeter displays less than 1.75 volts AC,
check the air gap as described in the following
steps before replacing the sensor. Verify that the
magnetic pickup air gap is 0.5 mm (0.020 in.).
Measure the air gap at 3 or 4 places to get an
accurate reading. See Figure 5-14.
a. Stop the generator set.
panels as required to gain access to the front of
the engine.
b. Remove the engine blower housing.
c. Use a feeler gauge to check the gap. The gap
should be 0.5 mm (0.020 in.).
d. Adjust the air gap, if necessary, by loosening
the locknut and turning the pickup.
Figure 5-14.
e. Hold the pickup in position and retighten the
locknut.
f. Verify the magnetic pickup air gap after
tightening the locknut.
g. Reinstall the engine blower housing.
h. Reinstall the junction box and housing panels
removed to gain access to the front of the
engine.
Figure 5-13 Magnetic Pickup Leads
Remove housing
See
6196
TP-6196 5/04