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Chapter 10
Crankshafts, Camshafts and Lubrication
Crankshafts
Do not attempt to straighten a
bent crankshaft. Doing so will
damage gears, and result in engine failure.
Inspect crankshaft for worn, scratched or damaged
bearing surfaces, out-of-round or flat spots on the
journal area, or a bent P.T.O. end.
When servicing crankshaft,
lubricate all bearing surfaces
prior to assembly. Leaving these parts dry could
accelerate wear at start-up.
When installing a crankshaft, lubricate all bearing surfaces
and use oil seal protector part no. 670327.
Crankshaft Timing Mark
The crankshaft has a pressed-on timing gear. This gear
has a small dimple punched on one of the teeth on this
gear.
2:30
This dimple is a timing mark. With the crankpin at top
dead center, the timing mark should be in the 2:30
position.
NOTE
Timing marks on crankshaft gear and camshaft gear must
be aligned for proper valve timing.
Camshaft Removal
Align timing marks to relieve valve train pressure. Lift
out cam.
The camshaft has a mechanical compression release
mechanism. A pin which runs through both cam lobes
extends past the exhaust lobe and lifts the valve to relieve
compression for easier starting. When the engine starts,
centrifugal force moves the flyweight outward, moving the
pin below the lobe, allowing full compression.
NOTES
The compression release mechanism is nonserviceable.
Replace camshaft assembly if damaged or worn.
The camshaft has been relieved in the intake lobe area.
This change was made to accommodate added crankshaft
counterweight material for improved engine balance.
Compression Release
Mechanism
Crankshaft
Counterweight
Relief
10-1
CAUTION
CAUTION
