DETROIT DIESEL
Engine Tune-Up
LIMITING SPEED MECHANICAL GOVERNOR AND INJECTOR RACK CONTROL ADJUSTMENT
IN-LINE ENGINES
The double-weight limiting speed governor is mounted
3.
Start the engine and adjust the idle speed screw
on the rear end plate of the engine and is driven by a
(Fig. 7) to obtain the desired engine idle speed. Hold
gear that extends through the end plate and meshes
the screw an tighten the lock nut to hold the adjustment.
with either the camshaft gear or the balance shaft gear,
depending upon the engine model.
NOTE: The recommended idle speed for non-
EPA certified engines is 500-600 rpm, but may
After adjusting the exhaust valves and timing the fuel
vary with special engine applications.
injectors, adjust the governor and position the injector
rack control levers.
4.
Stop the engine, clean and remove the governor
cover and the valve rocker cover. Discard the gaskets.
NOTE: Before proceeding with the governor
and
injector rack adjustments, disconnect
any
5.
Start and run the engine, between 800 and 1000
supplementary governing device.
After
the
rpm by manual operation of the injector control tube
adjustments are completed, re-connect
and
lever.
adjust the supplementary governing device.
CAUTION: Do not overspeed the engine.
Adjust Governor Gap
6. Check the gap between the low-speed spring cap
and the high-speed spring plunger with a .0015 " feeler
With the engine stopped and at operating temperature,
gage. If the gap setting is incorrect, reset the gap
adjust the governor gap as follows:
adjusting screw (Fig. 1). If the setting is correct, the
.0015" movement can be seen by placing a few drops of
1.
Remove the high-speed spring retainer cover.
oil into the governor gap and pressing a screw driver
against the gap adjusting screw. Movement of
2.
Back out the buffer screw (Fig. 8) until it
extends approximately 5/8" from the lock nut.
Fig. 1 - Adjusting Governor Gap
Fig. 2 - Positioning the Rear Injector Rack
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