Table 4-1.Governor Probable Causes and Corrective Actions Chart
Problem
Engine hunts or surges
Governor rod end jiggles
Probable Cause
Compensating needle valve
adjustment incorrect
Dirty oil in governor
Low oil level
Foamy oil in governor
Lost motion in engine governor
linkage or fuel pumps
Governor worn or incorrectly
adjusted
Engine misfiring
External fuel linkage sticking or
binding
Rough engine drive
Governor base not bolted down
evenly
Corrective Action
Make needle valve adjustment;
ensure that the opposite needle valve
is closed
Drain oil; flush governor; refill
Fill to correct level with clean oil
Drain oil; refill
Repair linkage and realign pumps
Remove governor and make internal
checks for clearances according to
applicable instructions
Test and replace injectors
Disconnect fuel rack from governor
and manually move linkage and
progressively disconnect fuel pump
links until binding area is found (dirt,
paint, and misalignment are the usual
causes of binding)
Check alignment of gears; inspect
for rough gear teeth; check backlash
of gear
Loosen bolts; realign and secure
to governor control unless the speed adjustment of the
load changes.
JIGGLES: High-frequency vibrations of the
governor fuel rod end or engine fuel linkage. Do not
confuse jiggle with the normal regulating action of the
governor.
When normal governor adjustments do not give the
desired response, the hydraulic governor should be
removed and you should send it to a repair activity for
cleaning, overhaul, and recalibration. You should have
a spare governor so that the engine can be operated
during the governor overhaul period and other PMS that
require removal of the original governor.
MECHANICAL GOVERNORS
The Navy generally uses the spring-loaded
In the idling speed range, control is effected by
flyball-type mechanical governors. All flyball-type
centrifugal force on the two sets of large and small
mechanical governors have speed droop. This means, as
flyweights, as shown in figure 4-1. This flyweight force
the load is increased at a constant throttle setting, the
acts against a light (low-speed) spring. Maximum speed
speed of the engine will drop or droop slightly, rather
than remain constant. Consequently, mechanical
governors of this type are never used where absolute
constant speeds are necessary.
Besides the spring-loaded flyball-type governors,
there are several other types of mechanical governors.
The two most common types are used on GM 71
engines. One type, the constant-speed governor, is used
on generator sets and is designed to hold the speed of
the engine at a predetermined operating speed. The other
type, similar in construction, is used primarily for
propulsion engines. It has a throttle plate designed so
that intermediate speeds may be obtained by manual
adjustment. Notice that there is no buffer spring
adjustment on the constant-speed governor. The
following description applies to both types of governors.
4-2