Engine and Controls (cont.)
Trouble, Symptom & Condition
Test or Inspection
Corrective Action
c. Loose or binding governor
linkage.
d.
Check linkage ball joints and all
connections for looseness or
binding. Be sure linkage will
move from idle speed to full
speed without lost motion or
binding.
e. GAIN and STABILITY
controls improperly
adjusted.
Adjust GAIN and STABILITY
controls on control unit in accor-
dance with 2-3; Para. 4, E, (3).
f. Magnetic pickup signal
weak.
Check and adjust pickup. See
2-3, Para. 3, E, (2).
9.
Engine has slow response time.
a. Governor control unit
improperly adjusted.
Adjust. See 2-3; Para. 3, E, (3).
b. Actuator linkage binding.
Inspect and repair as required.
c. Engine needs tune-up.
Tune up as required. Refer to
Detroit Diesel Operator’s
Manual.
10. Engine “misses”. Runs
unevenly.
a. Insufficient fuel.
Check fuel flow in accordance
with Para. 9, F. Repair or
replace parts as required. Also
see ENGINE, Trouble 3.
b. Faulty injector.
Check injectors in accordance
with Para. 9, B.
c. Low compression pressure.
Check compression in accor-
dance with Para. 9, C. See
causes of low compression
listed under ENGINE, Trouble
3, B, above.
11. Engine lacks power.
a. Improper engine
adjustment and gear train
timing.
“Tune-up” the engine in
accordance with Detroit Diesel
Operator’s Manual.
b. Insufficient fuel.
See ENGINE, Trouble 3.
c. Insufficient inlet air.
Check as follows:
d. Damaged air cleaner.
Check air cleaner for “plugging”
and/or other damage.
e. Defective blower to-cylinder
block gasket
Replace the gasket if
necessary. If the blower is
removed, install a new gasket.
f. Plugged cylinder liner ports.
Clean ports if they are over
50% obstructed.
g. Faulty air blower.
Repair or replace.
h. Worn Engine.
See engine overhaul
instructions in engine manual.
OM-2040 / Operation and Maintenance Manual
90D20 / Generator Sets
Chapter 3-1
February 28/94 Revised
Page 16
Summary of Contents for 6921 Series
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