Kohler 8.5RES Service page 87

7. To test the controller's governing function,
disconnect the magnetic pickup leads and open
the generator set circuit breaker.
8. Manually move the throttle shaft/governor stepper
motor fully counterclockwise (closed throttle).
9. Start the generator set. The stepper motor should
step clockwise to the wide open throttle position.
The stepper motor should remain in the clockwise
(throttle fully open) position. If the stepper motor
does not operate as described here, proceed to the
next steps to check the governor and stepper
motor.
10. Place the generator set master switch in the STOP
position. Check the stepper motor connections to
the controller: Leads 1A, 1B, 2A, and 2B to pins
P1-4, P1-5, P1-6 and P1-7. Check the pins and
connections at plugs J6 and P6. See the wiring
diagrams in Section 8.
11. Check the stepper motor coil resistance across
pins 2 and 3 and across pins 1 and 4. Only two
stepper motor leads of each coil group are used
(BLK-YEL and RED-WHT). See Figure 6-24. The
resistance per half coil is 38.5 ohms. If one of the
coils has a significantly higher resistance or is
shorted, replace the stepper motor.
TP-6196 10/09
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PIN 3, BLK
PIN 2, YEL
PIN 5, GRN
(not used)
PIN 4,
RED
Figure 6-24 Actuator Coil Group
12. If there is power and a good ground connection to
the ADC controller and the stepper motor coil
resistances are good, but the stepper motor does
not operate as described in step 9, the problem is
with the ADC controller.
connections, fuses, wiring, and settings. Refer to
the troubleshooting procedures in Section 3.
Section 6 Component Testing and Adjustment
PIN 1, PIN 6, BLUE
WHT (not used)
SB555
Check controller
87