Crankshaft, Camshaft And Lubrication; Crankshaft Timing Mark; Camshaft Timing Mark; Compression Release - Tecumseh VLV Technician's Handbook

CRANKSHAFTS, CAMSHAFTS
CRANKSHAFTS. 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.
CAUTION: Never try to straighten a bent crankshaft.
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. This dimple is a timing mark. With the crankpin
at top dead center, the timing mark should be in the
2:30 position.
The camshaft has an aligning mark in line with the timing
hole on the camshaft gear. Line this mark up with the
dimple on the crankshaft gear.
Timing marks on crankshaft gear and camshaft gear
must be aligned for proper valve timing.
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Chapter 10
AND LUBRICATION
CAMSHAFT REMOVAL:
Align timing marks to relieve valve train pressure. Lift
2:30
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.
The compression release mechanism is nonserviceable
(replace camshaft assy. 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.
Not For Resale

COMPRESSION RELEASE

MECHANISM
CRANKSHAFT
COUNTERWEIGHT
RELIEF
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