Prime mover will
not accept full
load.
Is the governor at full
fuel?
YES—
1. Is the linkage adjusted properly?
2. Is load excessive?
3. Is the voltage regulator (if used) set properly?
4. Is the fuel stop on the prime mover set correctly?
NO—
1. Is the load limit out of the way, and adjusted properly?
2. Is the fuel limited (if so equipped) set too low?
3. Is there adequate air pressure for the fuel limiter?
4. Is the linkage sticky or improperly adjusted?
5. If electric start fuel limiter—is there adequate voltage for the
solenoid?
Needle valve
adjustment does
not eliminate
instability.
(1) Are the oscillations
periodic and smooth
(not intermittent)?
YES—
Go to question (2).
NO—
Check the following:
1. Is the fuel source adequate and constant?
2. Is the speed setting reference steady?
3. Is the governor oil level low?
4. Is the load erratic?
5. Is the governor oil clean?
(2) Is the frequency of
the oscillation above 5
Hz?
YES—
Check the following:
1. Governor drive train.
2. Governor alignment.
3. Dirty spring-driven oil damped ballhead (if so equipped).
4. Bad injector or misfire?
NO—
Go to question (3).
(3) Are the oscillations
related to speed setting
variations?
YES—
The cause of the speed setting variation must be found and
corrected.
NO—
Go to question (4).
(4) Does the oscillation
disappear when
blocking governor
output or operating
hand throttle?
YES—
1. Is linkage loose or worn?
2. Is governor part number correct for this application?
3. Replace governor.
NO—
1. Check for load fluctuations.
2. Check fuel supply.
3. Check for loose or sticky linkage.
When blocking governor output or operating the hand
throttle, the system is not under governor control, and
extreme caution must be taken to prevent overspeed. Do
not attempt if overspeed speed device is not functioning.
Governor will not
shut prime mover
down.
Is governor at minimum
fuel position?
YES—
Linkage is improperly set to allow shutdown.
NO—
1. Is shutdown actuation signal available at the governor?
2. Are shutdowns properly adjusted?
3. Is shutdown strap in governor properly adjusted?
4. Close off fuel and replace governor.
