TM 5-3895-359-14&P
ENGINE TUNE-UP
CHAPTER 10
CONTENTS
PAGE
Engine Tune-Up Procedures and Emission ..............................................................................
Exhaust Valve Clearance Adjustment ........................................................................................
Fuel Injector Timing....................................................................................................................
Variable Speed Mechanical Governor and Injector Rack Control Adjustment ........................
ENGINE TUNE-UP PROCEDURES
There is no scheduled interval for performing an engine
Use a new valve rocker cover gasket after the tune-up is
tune-up.
As long as the engine performance is
completed.
satisfactory, no tune-up should be needed. Minor
adjustments in the valve and injector operating
Tune-Up Sequence for Mechanical Governor
mechanism, governor, etc. should only be required
periodically to compensate for normal wear on parts.
NOTE: Before starting an engine
after an engine speed control
To comply with emissions regulations, injector timing,
adjustment or after removal of the
exhaust valve clearance, engine idle and no-load
engine
governor
cover,
the
speeds, must be checked and adjusted, if necessary
serviceman must determine that the
(refer to Page 10-10-2).
injector racks move to the no-fuel
position when the governor stop
Normally, when performing a tune-up on an engine in
lever is placed in the stop position.
service, it is only necessary to check the various
Engine overspeed will result if the
adjustments for a possible change in the settings.
injector racks cannot be positioned
However, if the cylinder head, governor or injectors
at no-fuel with the governor stop
have been replaced or overhauled, then certain
lever.
preliminary adjustments are required before the engine
is started.
1. Adjust the exhaust valve clearance.
The preliminary adjustments consist of the first four
2. Time the fuel injectors.
items in the tune-up sequence. The procedures are the
same except that the valve clearance is greater for a
3. Adjust the governor gap.
cold engine.
4. Position the injector rack control levers.
To tune up an engine completely, perform all of the
adjustments, in the applicable tune-up sequence given
5. Adjust the maximum no-load speed.
below after the engine has reached normal operating
temperature. Since the adjustments are normally made
6. Adjust the idle speed.
while the engine is stopped, it may be necessary to run
the engine between adjustments to maintain normal
7. Adjust the buffer screw.
operating temperature.
8. Adjust the throttle booster spring.
10-10-1
