Engine Lubrication System - BRP Johnson 4HP Service Manual

Engine Lubrication System

A camshaft driven trochoid type pump provides engine oil to all powerhead components requiring lubri-
cation. Oil from the bottom of the crankcase is drawn through the oil filter and is pumped.
The oil is passed through the passage in the camshaft lubricating the journals, then through the internal
passage in the top of the cylinder to the crankshaft upper bearing.
From the periphery of crankshaft upper bearing and the camshaft upper journal, the oil runs down and
lubricates the each component by splash method.
ENGINE OIL LUBRICATION CHART
CRANKSHAFT UPPER BEARING
• PUSH ROD
• ROCKER ARM
• VALVE STEM
Through cylinder head /
Cylinder block passage
• CAM FACE
• TAPPET
• CRANK PIN
• TIMING GEAR
• CYLINDER WALL
• PISTON / RING
• PISTON PIN
• CRANKSHAFT
• LOWER JOURNAL
CRANKCASE
*: Splashed oil
CAMSHAFT UPPER
JOURNAL
CAMSHAFT OIL
PASSAGE
CAMSHAFT LOWER
JOURNAL
OIL PUMP
OIL FILTER
POWERHEAD
OPERATION
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