Thermo King UT-1200, Manual

Page: 107 / 169

Engine Maintenance
107
6. Place the O-ring in the groove in the end of
the fuel injection pump. Make sure that the
O-ring is positioned correctly during
installation to avoid damage and leaks.
7. Install the new fuel solenoid.
8. Press the
O
FF
key to turn the unit off after
installing the fuel solenoid.
Engine Speed Adjustments
When the diesel engine fails to maintain the
correct engine speed, check the following before
adjusting the speed:
1. Check the electric fuel pump filter. Recheck
the speed.
2. Check the operation of the electric fuel pump.
3. Bleed the air out of the fuel system. Recheck
the speed.
Make the engine speed adjustments with the
engine fully warmed up.
Low Speed Adjustment
1. Start the unit and let it run until the engine is
warmed up.
2. Adjust the setpoint to make the engine run in
low speed (or use Service Test Mode LSC)
and check the engine speed. The engine speed
should be 1450 ± 25 rpm for the UT-800, or
1625 ± 25 rpm for the UT-1200.
3. If the engine speed is not correct, loosen the
jam nut on the low speed adjustment screw.
4. Turn the low speed adjustment screw to
change the engine speed. Turn the screw in to
increase the engine speed. Turn the screw out
to decrease the engine speed.
5. Set the engine speed at 1450 ± 25 rpm for the
UT-800, or 1625 ± 25 rpm for the UT-1200
and tighten the jam nut.
6. Recheck the engine speed.
High Speed Adjustment
1. Start the unit and let it run until the engine is
warmed up.
2. Adjust the setpoint to make the engine run in
high speed (or use Service Test Mode HSC)
and check the engine speed. The engine speed
should be 2200 ± 25 rpm for the UT-800, or
2425 ± 25 rpm for the UT-1200.
3. If the engine speed is not correct, loosen the
jam nut at the end of the ball joint attached to
the throttle solenoid.
4. Snap the ball joint off of the throttle lever and
turn it to adjust the engine speed. Reinstall the
ball joint on the throttle lever.
5. Check the engine speed. Repeat step 4 as
necessary to set the engine speed at 2425 ± 25
rpm and tighten the jam nut.
1. Fuel Solenoid
2. O-ring
3. Groove in Fuel Injection Pump
Figure 179: Fuel Solenoid Components
AEA635
1. Low Speed Adjustment Screw
Figure 180: Low Speed Adjustment Screw Location
1