Inspect Oil Pump; Horizontal Crankshaft Models; Vertical Crankshaft Models - Briggs & Stratton Twin Cylinder L-Head Repair Manual

A pressure relief valve located in the oil filter adapter, Fig. 31, or optional remote oil filter adapter, Fig. 32, limits the
maximum oil pressure in the system.
Examine pressure relief valve seat for proper seating. Seat must have no nicks or burrs. Pressure relief valve spring
length is 1.125" ± .034" (28.6 ± .86 mm). Replace spring if length is greater, or less than this tolerance, Fig. 31.
Fig. 31 – Pressure Relief Valve

INSPECT OIL PUMP

Horizontal Crankshaft Models

1. With crankcase cover removed, examine oil pump
drive gear for worn, chipped or cracked teeth.
Replace gear if any of these conditions are found.
2. Remove the drive gear retaining ring and drive
gear.
3. Remove the three (3) pump mounting screws.
4. Remove the pump assembly and check the rotors
and shaft, Fig. 33.
If any obvious damage or excessive wear is noted,
replace the pump assembly. Torque pump mounting
screws to 50 in. lbs. (6.0 Nm). The oil pump is virtually
trouble free and requires very little service.

Vertical Crankshaft Models

The oil pump rotors can be inspected and/or replaced
without removing the sump.
1. Remove 3 pump cover screws and cover.
2. Remove rotor and shaft assembly and outer rotor,
Fig. 34.
3. Check rotors and shaft for any obvious wear and/
or damage. Replace as necessary.
If pump housing is worn or damaged, replace sump.
Check "O"-ring in pump cover. Replace if damaged.
Torque pump cover screws to 50 in. lbs. (6.0 Nm). The
oil pump is virtually trouble free and requires very little
service.
OIL FILTER
ADAPTER
PRESSURE RELIEF
VALVE
1.125 " .034"
CHECK BALL
(28.57 " .86 mm)
FREE LENGTH OF SPRING
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PRESSURE RELIEF
VALVE HOUSING
OIL FILTER
ADAPTER
Fig. 32 – Optional Remote Filter
Fig. 33 – Remove Oil Pump
Horizontal Crankshaft Models
TORQUE
SCREWS
TO 50 in. lbs.
ROTOR
(5.7 Nm)
"O"-RING
OUTER
ROTOR
RETAINER
PUMP
RING
COVER
Fig. 34 – Remove Oil Pump
Vertical Crankshaft Models
DRIVE
GEAR
RETAINING
RING
SCREWS (3)
TORQUE
SCREWS
TO 50 in. lbs.
(5.7 Nm)
PUMP
HOUSING
ROTOR AND
SHAFT
OUTER
ROTOR
SHAFT
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