Generac Power Systems 941-2 Service Manual page 109

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