c. Unloader pilot out of adjust-
Adjust unloader pilot (par. 107).
ment.
d. Leaks in gaskets or air line
Check fittings. Replace worn gaskets
fittings.
(pars. 124 and 126).
e. Worn or broken piston rings.
Replace piston rings (par. 223). See
note in paragraph 48.
57. Unit Stalls Before Loading
Probable cause
Possible remedy
a. Suction valve unloader
Replace defective parts (par. 126).
plunger is stuck.
b. Pilot valve air liner loose.
Tighten air liner.
c. Check and bleed valve out of
Adjust check and bleed valve
adjustment.
(par.106).
d. Diaphragm end screws loose.
Tighten diaphragm end screws.
58. Compressor Cylinder Bank Knocks
Probable cause
Possible remedy
a. Low oil level.
Fill crankcase to FULL mark on oil
level gage.
b. Loose or worn connecting rod
Replace connecting rod bearings
(par. 223). See note in paragraph 48.
c. Loose or worn piston pins.
Replace piston pins (par. 223). See
note in paragraph 48.
59. Unloader Pilot Chatters
Probable cause
Possible remedy
Differential pressure range set
Adjust unloader pilot (par. 107).
too close.
60. High or Low Air Pressure Gage
Reading
Probable cause
Possible remedy
a. Unloader pilot out of adjust-
Adjust unloader pilot (par. 107).
ment.
b. Intake valve unloader plunger
Replace defective parts (par. 126).
is stuck.
c. Faulty air pressure gage.
Replace air pressure gage (par. 102d).
61. Low Oil Pressure
Probable cause
Possible remedy
a. Lack of oil.
Fill crankcase to FULL mark on oil
level gage.
b. Oil sludge.
Drain and refill crankcase with fresh
oil. Replace oil-filter elements.
c. Clogged suction screen.
Remove, clean and reinstall suction
screen (par. 218). See note in
d. Sticking pressure relief valve.
Remove, clean and reinstall relief valve
(par. 219). See note in paragraph 48.
e. Clogged lines to oil pressure
Disconnect and clean oil line (par. 219).
gage or defective gage.
See note in paragraph 48. Replace
oil pressure gage if necessary
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