O.S. Engines 91HZ-R 3D - 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.
With this engine, the cover plate cannot
be removed when the piston is at BDC
due to engine construction.
When it is required to remove the cover
plate, be sure to position the piston at
TDC.
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