PROPELLER & SPINNER ATTACHMENT
There is a risk, particularly with powerful four-
stroke engines, of the propeller flying off if the
prop nut loosens due to detonation
("knocking") in the combustion chamber when
the engine is operated too lean, or under an
excessively heavy load.
Obviously, this can be very hazardous. To
eliminate such dangers, the O.S. Safety
Locknut Assembly was devised.
1. Ream the propeller shaft hole to 6.4-6.5mm
bore with an appropriate reamer, checking
that the hole is exactly centered.
2. Install the prop to the engine shaft, followed
by retaining washer and prop nut lightly.
Turn the prop counter-clockwise slowly to
locate the position where compression is
felt. At this position, fit the prop horizontally
and tighten firmly the prop nut with a 13mm
wrench.
3. Add the specially tapered and slotted
locknut and secure with a 10mm wrench
while holding the prop nut with the 13mm
wrench.
Propeller Washer
Lock Nut
Propeller Nut
4. Fit a spinner assembly to start the engine
with an electric starter.
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