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Note: When re-starting the engine on the
same day, provided that atmospheric
conditions have not changed significantly,
it may be practicable to re-start the engine
on its optimum (running) setting. Also, if
the engine is being re-started immediately
after a run (i.e.hot), priming should not be
necessary.
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How to stop the engine
Close the throttle to reduce to the lowest
possible r.p.m.
Close
With the transmitter throttle trim lever fully
retarded, adjust the throttle servo linkage so
that the throttle rotor is fully closed (i.e.engine
stopped) when the stick is fully retarded.
RUNNING-IN ("Breaking-in")
All internal-combustion engines benefit, to
some degree, from extra care when they are
run for the first few times - known as running-in
or breaking-in. This is because the working
parts of a new engine take a little time to settle
down after being subjected to high
temperatures and stresses. However, because
O.S. engines are made with the aid of the
finest modern precision machinery and from
the best and most suitable materials, only a
very short and simple running-in procedure is
required and can be carried out with the
engine installed in the model.
The process is as follows:
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1) Start the engine and, with the throttle fully
open, open the needle-valve an extra half
turn (180˚) from the optimum setting. This
will produce a rich mixture that will result in
cooler running. Allow the engine to run out
a full tank on the ground. (Avoid dusty
surroundings.)
2) Now fly the model with the needle-valve re-
set 20-30 degrees open from the optimum
setting (i.e. 40-60˚ from the highest rpm
setting).
3) Close the needle-valve very slightly on
successive flights so that the engine is
running on its optimum needle setting at the
fifth or sixth flight.
These engines are equipped with a throttle
type car-burettor which provides a wide range
of engine speed control. With the throttle lever
linked to a suitable electric servo in the model,
movement of the throttle control on the
transmitter will enable engine rpm to be varied,
proportionally, from idling speed to full power.
The carburettor of your engine has been
factory set for the approximate best results and
no adjustment (except to the needle-valve)
should be required provided that the fuel tank
is correctly located, as previously described.
After the engine has been run-in, check the
operation of the throttle according to the
following chart. Re-adjust the controls only
when necessary.
CARBURETTOR
