Mechanical Compression Release - Tecumseh V-twin Technician's Handbook

CAUTION: NEVER ATTEMPT TO STRAIGHTEN A
BENT CRANKSHAFT.
Inspect the crankshaft oil galleys for blockage or
obstruction. (Illust. 7-32)
CAMSHAFTS
Check the camshaft bearing surfaces for wear using a
micrometer. Inspect the cam lobes for scoring or
excessive wear.
Specifications
Camshaft Bearing Diameter
Cylinder and Flange
Camshaft Bearing Diameter
7-12
7-32
English Std. Metric
.6235 15.836
.6240 15.849
.6245 15.862
.6255 15.887

MECHANICAL COMPRESSION RELEASE

The Mechanical Compression Release (MCR)
incorporates pins located in the camshaft. The pins
extend above the exhaust cam lobes, lifting the valve
and relieving engine compression for easier starting.
When the engine starts, centrifugal force moves the
weight outward and the pin will drop back down. The
engine will now run at full compression.
The components of the MCR except for the internal pins
are serviceable. When servicing the MCR be cautious
not to misplace the pins, as a new camshaft would be
necessary.
Clean the camshaft with solvent and dry all parts with
compressed air. Make sure that the pins, weight and
shaft of the mechanical compression release are
operating freely and smoothly. (Illust. 7-33)
7-33