193Section 10 Governor AdjustmentsTP-6356 4/12
3. Slowly back out the high idle screw while holding
the engine speed lever in the high idle position until
you obtain the desired frequency.
4. Tighten high idle locknut to 4--5 Nm (35--45 in. lb.).
5. Turn in the low idle screw to lock lever in place and
tighten low idle locknut to 4--5 Nm (35--45 in. lb.).
6. Readjust the frequency with the INC/DEC buttons
on governor controller to bring the frequency to
67 Hz for 60 Hz models and 56 Hz for 50 Hz
models.
7. With no load applied, increase the overall gain until
the engine begins to hunt.
If the engine does not begin to hunt, momentarily
disrupt the governor power supply. Then decrease
the overall gain until stable.
For optimum performance, the engine should
oscillate 3--5 diminishing cycles after being
disrupted.
Troubleshooting
If the governor system fails to operate and the actuator is
suspected to be the problem, perform the following
tests.
Measure the actuator coil resistance. The values shown
in Figure 10-7 are for readings at ambient temperature.
Actuator Resistance, ohms
12 VDC 2.05 ±0.25
24 VDC 7.20 ±0.50
Figure 10-7 Actuator Coil Resistance Values
Measure the coil isolation. The coil to case resistance
should be >3 megohms.
Remove the actuator from the generator set. Manually
move the actuator through its range of motion. No
binding or sticking should occur.
Before testing the actuator, place a diode (Motorola P/N
MUR810 or equivalent) across the actuator terminals.
Energize the actuator to full fuel position. The actuator
should operate smoothly throughout its entire stroke
without any interruptions in motion.
If the actuator passes these tests, the problem is likely in
the governor controller and/or fuel system.
10.3 Mechanical Governor
10.3.1 Stanadyne DB2/DB4
Note: Before checking and adjusting engine speed,
make sure engine has reached its normal
operating temperature.
All speeds indicated apply to a hot engine under load.
The maximum permissible speed variation is 50 rpm for
fast idle speed.
1. Disconnect speed control from fuel injection pump
lever.
2. Move the generator set master switch to the RUN
position to start the generator set.
3. Verify that injector pump lever is held in fast idle
position against fast idle adjusting screw. See
Figure 10-8.
TP-5353-7
12
1. Injection Pump Lever
2. Fast Idle Adjusting Screw
Figure 10-8 Governor Adjustments, Typical
4. Using a tachometer, check engine speed. Adjust
engine speed to obtain a full load engine speed of
1800 rpm (60 Hz) or 1500 rpm (50 Hz).
To increase engine speed, rotate fast idle adjusting
screw CCW; rotate fast idle adjusting screw CW to
decrease engine speed.
5. Reconnect speed control to fuel injection pump
lever.
6. Move the generator set master switch to the OFF/
RESET position to stop the generator set.
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