ENGINE
3.11
OIL FLOW -- EH50PL
The chart on Page 3.12 describes the flow of oil
through the EH50PL engine. Beginning at the oil tank,
the oil flows through a screen fitting in the bottom of
the tank and into the oil supply hose. The feed side
of the oil pump draws oil through the hose and into the
crankcase oil gallery, and then pumps the oil through
another passage to the one way valve. (When the
engine is off, the one way valve closes to prevent oil
in the tank from draining into the crankcase.) The oil
is pumped through a delivery pipe to the oil filter. If the
oil filter is obstructed, a bypass valve contained in the
filter allows oil to bypass the filter element.
At this point, the oil is diverted in two directions. Oil
is supplied to the camshaft through the left front
cylinder stud, and an oil passage in the head. Oil
enters the camshaft through the PTO (L) journal. The
camshaft journals, cam lobes, and rocker arms are
lubricated through holes in the camshaft.
The oil
lubricates the cam chain and sprocket and drains to
the sump.
The other oil path from the filter leads through a
delivery pipe to the crankcase main oil gallery, which
leads to the stator plate oil passage. Here it passes
through the slotted friction bearing (located in the
stator plate) into the crankshaft. An oil seal on the
stator
plate
prevents
oil
from
entering
the
stator/flywheel area.
Oil travels through the
crankshaft to the crank pin, lubricating the connecting
rod large end bearing directly. Oil also passes through
an oil jet (drilled orifice) in the end of the crank pin to
the PTO end main bearings and counterbalancer
gears.
Residual oil from the lubrication of the crankshaft and
connecting rod indirectly lubricates the cylinder wall,
piston, rings, connecting rod small end bearing, piston
pin, oil/water pump drive gears, cam chain and drive
sprocket, and Magneto end crankshaft main bearing.
The one-way valve is located on the front left (PTO)
side of the crankcase. The valve prevents oil in the
tank from draining into the engine sump when the
engine is off. The valve mechanism consists of a
plunger, return spring, guide plug, and sealing
washer. When the engine is running, oil pressure lifts
the plunger off the seat, allowing oil flow. When the
engine is off, spring pressure forces the plunger
against the oil passage seat, preventing oil flow from
the tank to the sump. The one-way valve requires
very little maintenance. If engine oil drains into the
sump when the engine is off, inspect the valve sealing
surface for debris or damage.
Inspect the return
spring for distortion or damage.
Enfocus Software - Customer Support
Summary of Contents for SPORTSMAN 400 2003
Page 1: ...2003 SPORTSMAN 400 500 SERVICE MANUAL PN 9918065 The Way Out ...
Page 5: ......
Page 51: ...MAINTENANCE 2 32 NOTES ...
Page 71: ...ENGINE 3 20 CYLINDER HEAD EXPLODED VIEW EH50PL A EH50PL ...
Page 131: ...BODY STEERING SUSPENSION 5 12 NOTES ...
Page 165: ...CLUTCH 6 34 NOTES ...
Page 193: ...FINAL DRIVE 7 28 NOTES ...
Page 217: ...TRANSMISSION 8 24 NOTES ...
Page 239: ...BRAKES 9 22 ...
Page 274: ...PN 9918065 Printed in USA ...