Section 12: Lubrication; General; Oil Flow; Oil Pickup Assembly - Generac Power Systems GN190H Service And Repair Manual

SECTION 12: LUBRICATION

GENERAL

The engine lubrication system serves to (a) reduce friction
between moving parts, (b) cool the engine and (c) estab-
lish a negative pressure in the crankcase to prevent oil seal
leakage.
Major components include the following:

• Oil pickup assembly.

• Oil pump.

• Crankshaft oil seals.
• Pressure relief valve.
• Breather assembly.
• Crankcase cover.
• Low oil pressure switch.

OIL FLOW

See Figure 12.1. The oil pump draws crankcase oil through
an oil pickup and delivers it to the areas requiring lubrication
as follows:
1. Through a cored channel in the crankcase cover and to the
crankshaft journal at the power take-off (PTO) end of the
crankshaft.
2. Through the hollow camshaft and to the camshaft bear-
ing at the flywheel end.
3. Through a cored passage in the crankcase housing and to
the crankshaft journal at the flywheel end.
4. Through the crankshaft to the crankpin and connecting rod
bearing.
1
Figure 12.1 — Lubrication System Diagram
4
3
2
OIL PICKUP ASSEMBLY

DESCRIPTION:

The oil pickup assembly consists of a plastic body and an
oil pickup screen. The pickup must be installed with its screen
facing downward toward the crankcase base. The tubular end
of the pickup fits into a bore in the crankcase cover. When
the crankcase cover is installed, a cast protrusion in the
crankcase prevents the pickup from coming out.
Figure 12.2 — Oil Pickup Assembly

INSPECTION:

Clean the pickup in solvent. Inspect the plastic body for
cracks or other damage. Check the screen for damage. Make
sure the hollow pickup tube is clean and free of obstructions.
DESCRIPTION:
The oil pump (Figure 12.3) is of the gerotor type. Its inner
rotor rotates on a shaft provided in the camshaft bore of the
crankcase cover. The outer rotor is installed over two drive
pins on the end of the camshaft and is driven by camshaft
rotation.
TO CRANKCASE
COVER
INNER
ROTOR
Figure 12.3 — Oil Pump
46
OIL PUMP
OUTER
ROTOR
CAMSHAFT