Engine Tune-Up
LIMITING SPEED MECHANICAL GOVERNOR AND INJECTOR RACK
CONTROL ADJUSTMENT
6, 8 and 12V-71 ENGINES
The two types of limiting speed mechanical governors
Adjust the Governor Gap
used on the V-71 engines are covered in this
p r o c e d u r e . The difference between each type of
With the engine stopped and at normal operating
governor is in the high speed spring retainer and
temperature, adjust the governor gap as follows:
spring housing assembly. Industrial engines use the
s t a n d a r d limiting speed governor, while some
1. Remove the two bolts and withdraw the governor
applications may find it advantageous to use the dual-
high speed spring retainer cover.
range limiting speed governor.
2. Back out the buffer screw until it extends approx-
imately 5/8" from the lock nut (Fig. 10).
The only variation in the tune-up procedure between
e a c h type of governor is in the setting of the
3. Start the engine and loosen the idle speed adjusting
maximum no-load speed. Therefore, the setting of the
screw lock nut. Then adjust the idle screw (Fig. 9) to
maximum no-load engine speed is given for each type
obtain the desired engine idle speed. Hold the screw
of limiting speed governor.
and tighten the lock nut to hold the adjustment.
After adjusting the exhaust valves and timing the fuel
IMPORTANT: Current turbocharged engines
injectors, adjust the governor and position the injector
include a starting aid screw threaded into the
rack control levers.
governor housing.
NOTE: Before proceeding with the governor and
NOTE: The recommended idle speed for non-
i n j e c t o r rack adjustments, disconnect any
EPA certified engines is 400-450 rpm, but may
supplementary governing device. After the
vary with special engine application.
a d j u s t m e n t s are completed, reconnect and
adjust the supplementary governing device.
4. Stop the engine. Clean and remove the governor
cover and lever assembly and discard the gasket.
5. Start and run the engine between 800 and 1000 rpm
by manual operation of the differential lever.
CAUTION: Do not overspeed the engine.
6. Check the gap between the low speed spring cap
and the high speed spring plunger (Fig. 1) with a
.0015" feeler gage. If the gap setting is incorrect, reset
the gap adjusting screw.
If the setting is correct, the .0015" movement can be
seen by placing a few drops of oil into the governor
g a p and pressing a screw driver against the gap
adjusting screw. Movement of the cap toward the
plunger will force the oil from the gap in the form of
a small bead.
7. Hold the gap adjusting screw and tighten the lock
nut.
8. Recheck the governor gap and readjust if necessary.
9. Stop the engine and, using a new gasket, install the
Fig. 1 - Adjusting Governor Gap
governor cover and lever assembly. Tighten the screws.
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