O.S. Engines 91HZ-R - 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 the similar into the
exhaust port.
It is recommended to use Crankshaft
Clamp 91 (Code No.71530510) available
as an optional tool.
7
Notes on installing cooling fan and clutch
Do not grip the engine mounting
beams with a vise, or the crankcase
will be distorted which will result in
engine breaking.
Vise
Beam Mount