72 Section 5 Component Testing and Adjustment TP-6844 1/13
• Check for electronic governor faults. The fuel
shutoff solenoid deenergizes and the generator set
shuts down under the following conditions:
◦ Closed throttle
◦ Engine overspeed
◦ Broken fuel shutoff solenoid lead
◦ Broken stepper motor leads (erratic
performance)
◦ Failed actuator linkage (erratic performance)
• Check the fuel supply pressure and the fuel supply
system for leaks, blockages, and/or failed system
components (regulators, valves, etc.). See Section
5.8, Fuel Systems.
5.6.3 Hunting/Surging
Hunting/surging problems thought to be caused by the
governor system are more likely to be caused by fuel
supply, engine, or carburetor problems. Check engine
speed stability using the following procedure before
testing the governor.
Servicing the exhaust system. Hot parts can cause
severe injury or death. Do not touch hot engine parts. The
engine and exhaust system components become extremely
hot during operation.
1. Open the generator set line circuit breaker.
2. Start the generator set.
3. Hold the throttle linkage steady while the engine
is running. See Figure 5-13. If the engine runs at
a steady speed with no hunting or surging when
the throttle is held steady, then the
hunting/surging problems during operation may
be caused by the governor. Proceed to Section
5.6.4.
4. Check the linkage between the stepper motor
and the carburetor. Replace any worn or
damaged components.
5. Verify that the speed control parameters have not
been modified. Reset the Engine Speed
Governor setting to the default setting. See
Figure 5-16.
6. If the engine speed hunts or surges while the
throttle is held steady, check the carburetor and
engine operation. Refer to the engine service
manual for engine diagnostic and service
information.
Figure 5-13
Figure 5-13 Stepper Motor and Carburetor
Hot engine and exhaust system.
Can cause severe injury or death.
Do not work on the generator set
until it cools.
1
2
3
KPS_096
1. Electronic governor stepper motor
2. Carburetor throttle linkage
3. Carburetor
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