O.S. Engines 37SZ-H - Manual (Page 4)

6
Notes on installing cooling fan and clutch
Do not use a tool which
locks piston when installing
a cooling-fan and clutch, or
top of the piston may be
damaged. Also, do not
insert a screw driver or
similar into the exhaust
port.
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It is recommended to use Crankshaft
Clamp 37 (Code No.71530600) available
as an optional tool.
It is made of durable engineering plastic
and locks the crankshaft without risk of
damage to any part of the engine.
Application is as follows:
Remove the crankcase rear cover plate from
the engine and rotate the crankshaft to the
bottom dead center (BDC) position.
Insert the crankshaft clamp so that its grooved
portion surrounds the crankpin and lower end
of the connecting rod and securely tighten the
fan or clutch onto the crankshaft.
Insert this groove onto
the connecting rod.
Rotate the crankshaft so that the
connecting rod comes to this position.
BDC position