Disassembly. Disassemble the oil filter as shown in figure 3-5.
Clean all parts in a well-ventilated area.
Avoid inhalation of solvent fumes and
prolonged exposure of skin to cleaning
solvent. Wash exposed skin thoroughly.
Dry cleaning solvent (fed. Spec. P-D-680)
used to clean parts is potentially
dangerous to personnel and property. Do
not use near open flame or excessive heat.
Flash point of solvent is 100 to 138 F (38 to
(2) Clean all remaining parts with cleaning
solvent (Fed. Spec. P-D-680). Use compressed air to
blow debris from tubes and hoses.
(3) Inspect the hose for abrasion, cracks,
deterioration, damaged threaded ends, and collapsed
walls; replace a damaged hose.
(4) Inspect the tube for dents, cracks,
damaged tube nuts, and collapsed walls; replace a
(5) Inspect the filter body and cover for
cracks, distortion, dents, damaged threads, and other
damage; replace a defective body or cover.
(6) Inspect the oil pressure sender for
cracks, dents, and damaged threads. Check the sender
in series with a 12-volt battery and the oil pressure gage
mounted on the control panel. Use a low pressure,
calibrated air supply when you run the test. The sender
must provide proper resistance at various pressures to
register the required readings on the associated gage.
Replace damage or inaccurate parts.
(7) Inspect all other parts for cracks,
distortion and damaged threads. Replace damaged
Reassembly and Installation. Reassembly
and installation are the reverse of removal and
disassembly. Refer to figure 3-4 and 3-5. After filling
the engine lubricating system with oil per LO 5-4320-
234-12, start the engine and check for oil leaks. Correct
3-15. Engine Oil Pressure Adjustment
Oil filter body
If oil pressure is consistently low, you can make
the necessary pressure adjustment as follows:
Start the engine and allow it to warm to
operating temperature. Check the engine oil pressure
indicated on the oil pressure gage. At idle speed the
Oil filter clamp
Figure 3-5. Oil filter assembly, exploded view
pressure must exceed 7 psi; at governed speed it must
be between 20 and 30 psi.
Cleaning and Inspection.
If the engine oil pressure is not within the
(1) Discard and replace the oil filter
required range, shut off the engine and remove the plug
element and gaskets.
(1, fig. 3-6) and gasket (2) from the carburetor side of
the engine block. Remove the valve spring (3) and
pressure adjusting washer (4).