Stepper Motor Check - Kohler COM7.5 Service Manual

The fuel shutoff solenoid deenergizes and the generator
set shuts down with the following electronic governor
faults:
D
Loss of pickup while running (throttle moves to closed
position)
D
Engine overspeed
D
Broken fuel shutoff solenoid lead
D
Loss of DC power to governor assembly
D
Broken stepper motor leads (erratic performance)
D
Actuator linkage failure (erratic performance)
If none of the above conditions exist, proceed to
Section 4.2.2, Stepper Motor Check.
1
1. Stepper motor
2. Throttle linkage
Figure 4-3 Governor
TP-6120 5/02
2
photos2-7
TP5867
4.2.2

Stepper Motor Check

Use the following procedure to test the operation of the
governor stepper motor.
Stepper Motor Test Procedure
1. Stop the generator set and disconnect the battery.
2. Manually move the governor linkage fully
counterclockwise (open throttle). See Figure 4-3.
3. Reconnect the battery. The stepper motor should
move clockwise to the closed-throttle position with
a noticeable clicking sound. If the stepper motor
does not stay in the closed-throttle position,
replace the stepper motor.
Only two stepper motor leads of each coil group are
utilized (BLACK-YELLOW and RED-WHITE).
resistance per phase is 38.5 ohms. See Figure 4-4.
BLK
YEL
GRN
Figure 4-4 Actuator Coil Group
Section 4 Component Testing and Adjustment
RED WHT BLU
The
SB555
25