TM 9-2330-356-14
b.
c.
a.
equipment test.
d.
and fig. 7-25) into the Number 1 cylinder fuel injector
Bench Tests.
b.
opening in the cylinder head. Secure the adapter to the
cylinder head with two 5/16-18 NC x 3/4 capscrews.
(1) Testing Starter.
NOTE
(a) If starting motor tests are required,
The best indication of compression leakage
remove the motor from the engine and test it on a bench.
is the pressure difference between cylinders.
Test the free-running voltage and current.
Compression of a standard new engine
(b) Using a spring scale and torque arm, test
cranking at about 300 rpm is approximately
350-400 psi. Maintenance should be
reading by the arm length for the torque value.
considered If pressure is below 325 psi or If
there Is a 15% or more difference between
(c) If free running speed is low, and starter
cylinders.
has a high current draw with low stall torque, check for
tight, dirty or worn bushings, bent armature shaft, or loose
e.
Turn the engine START switch to the start
field pole screws, allowing armature to drag. Check also
position to crank the engine. Record the compression
for shorted or grounded armature and field.
reading on the gage as the engine is being cranked.
Remove the compression gage and adapter.
(d) A low free speed with low torque and
f.
Insert adapter in Number 2 cylinder fuel injector opening.
low current draw indicates an open field winding, high
Secure with two capscrews.
internal resistance due to poor connections defective
leads, broken or worn brushes, or scored, worn, or dirty
Turn the engine START switch to the start
g.
commutator.
position and crank engine. Record the compression
reading on the gage as the engine is being cranked.
(e) High free speed with low developed
torque and high current draw indicates shorted fields.
Repeat steps f and g for Number 3 and Number 4
h.
Since there is no easy way to detect shorted field coils,
cylinders.
replace and check for improved performance.
i.
(f) The voltage drop across the solenoid on
j.
the starting motor should be less than 1.5 volts. If not,
k.
Replace shroud door panel.
remove it for repair.