Engine Tune-Up
DETROIT DIESEL
VARIABLE SPEED MECHANICAL GOVERNOR (ENCLOSED LINKAGE) AND
INJECTOR RACK CONTROL ADJUSTMENT
IN-LINE ENGINES
1. Disconnect any linkage attached to the governor
The single-weight variable speed governor is mounted
on the rear end plate of the engine and is driven by a
gear that extends through the end plate and meshes
2. Back out the buffer screw until it extends
with either the camshaft gear or the balance shaft
approximately 5/8" from the lock nut.
gear, depending upon the engine model.
3. Clean and remove the governor cover and valve
After adjusting the exhaust valves and timing the fuel
rocker cover. Discard the gaskets.
injectors, adjust the governor and position the injector
rack control levers.
4. Place the speed control lever (Fig. 1) in the
maximum speed position.
NOTE: Before proceeding with the governor and
5. Insert a .006" feeler gage between the spring
injector rack adjustments, disconnect any
plunger and the plunger guide as shown in Fig. 1. If
supplementary governing device. After the
required, loosen the lock nut and turn the gap
adjustments are completed, reconnect and
adjusting screw in or out until a slight drag is noted on
adjust the supplementary governing device.
the feeler gage.
6. Hold. the adjusting screw and tighten the lock nut.
Check the gap and readjust if necessary.
Adjust Governor Gap
7. Use a new gasket and install the governor cover as
follows:
With the engine stopped and at operating tempera-
ture, adjust the governor gap as follows:
a. Place the cover on the governor housing, with the
Fig. 2 - Positioning the Rear Injector Rack
Control Lever
Fig. 1 - Checking Governor Gap
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