Generac Power Systems 941-2 - Manual (Page 109)

Section 7.1
GENERATOR & SPEED CONTROL SYSTEM
PROBLEM POSSIBLE CAUSE REMEDY PAGE
1. Engine starts, accelerates, a. Carburetor linkage sticking with a. Repair sticking throttle 3.4-3
shuts down at 4500 rpm throttle stuck open.
b. Stepper Motor failed or seized.
b. Replace Stepper Motor. 3.6-1
c. Stepper Motor wire connections c. Reconnect or repair. 3.6-1
broken or disconnected.
d. Stepper Motor not properly connected.
d. Reconnect wires. 3.6-1
2. Overvoltage condition and a. Carburetor linkage sticking with a. Repair sticking throttle. 3.4-3
speed control system cannot throttle stuck partly open.
reduce output voltage. b. Stepper Motor failed or seized. b. Replace Stepper Motor. 3.6-1
c. Connection to Stepper Motor is c. Repair or replace connections. 3.6-1
broken/disconnected with throttle open.
d. Stepper Motor not properly connected.
d. Reconnect Stepper Motor wires. 3.6-1
3. Engine speed is maintained a. Carburetor linkage sticking with a. Repair sticking throttle. 3.4-3
and no-load voltage is good. throttle partly open.
However, when load is applied b. Stepper Motor failed or seized. b. Replace Stepper Motor. 3.6-1
output voltage drops. c. Connection to Stepper Motor c. Repair or replace connections. 3.6-1
Motor broken or disconnected.
d. Stepper Motor not properly
d. Reconnect Stepper Motor. 3.6-1
connected.
4. Engine does not accelerate a. Carburetor linkage sticking a. Repair sticking throttle. 3.4-3
when load is applied. with throttle stuck closed.
b. Stepper Motor failed or seized.
b. Replace Stepper Motor. 3.6-1
c. Stepper Motor not properly c. Reconnect Stepper Motor. 3.6-1
connected.
5. Engine speed and AC output a. Stepper Motor failure. a. Replace Stepper Motor. 3.6-1
voltage erratic under constant b. Connection to Stepper Motor b. Repair or replace connections. 3.6-1
load. AC output does not turn broken or disconnected.
off intermittently. c. Stepper Motor not properly c. Reconnect Stepper Motor. 3.6-1
connected
6. Engine starts but Stepper a. Stator Timing winding is open. a. Repair/replace bad wire(s) 1.5-2
Motor does not move. Shut down TIM1/TIM2 or replace Stator.
occurs after several seconds. b. Timing winding in Stator shorted b. Replace Stator. 1.5-2
to ground.
Page 7.1-1
TROUBLESHOOTING REFERENCE CHART