O.S. engine MAX-75AX Instruction Manual page 14

Attention :
Do not choke the carburetor air intake when
applying the starter. This could cause an
excessive amount of fuel to be drawn into the
cylinder which may initiate a hydraulic lock and
damage the engine.
If the engine does not start within 10 repeat
applications of the starter, remove the glow-
plug, check that it glows brightly and that the
cylinder is not flooded with fuel. (To eject
excess fuel, close needle-valve and apply
starter with glowplug removed.) Then try again.
VERY IMPORTANT!
Before being operated at full power (i.e. at full-
throttle and with the needle-valve closed to its
optimum setting) the engine must be adequately
run-in, otherwise there is a danger of it becoming
overheated and damaged.
RUNNING-IN ("Breaking-in")
All internal-combustion engines benefit from
extra care when they are run for the first few
timesknown as running-in or breaking-in.
This allows the working parts to mate together
under load at operating
Therefore, it is vitally important to complete the
break-in before allowing the engine to run
continuously at high speed and before
finalizing carburetor adjustments.
However, because O.S. engines are produced
with the aid of the finest modern precision
machinery and from the best and most suitable
materials, only a short and simple running-in
procedure is called for and can be carried out
with the engine installed in the model.
The process is as follows.
How to stop the engine
Pull down the throttle lever and trim lever on
the transmitter fully.
Note:
Make sure that the throttle linkage is set so
that the throttle is fully closed when the
throttle lever as well as trim lever on the
transmitter are fully pulled down.
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1.
Install the engine with the propeller intended
for your model. Open the needle-valve to the
advised starting setting and start the engine.
If the engine stops when the glow plug
battery is disconnected, closed the needle-
valve to the point where the engine does not
temperature.
stop.Run the engine for one minute with the
throttle fully open, but with the needle-valve
adjusted for rich, slow "four-cycle"operation.
2.
Now close the needle-valve until the engine
speeds up to "two-cycle"operation and allow it
to run for about 10 seconds, then reopen the
needle-valve to bring the engine back to "four-
cycle"operation and run it for another 10
seconds. Repeat this procedure until the fuel
tank is empty.
3. Re-start and adjust the needle-valve so that
the engine just breaks into a "two-cycle" from a
"four-cycle" operation, then make three or four
flights, avoiding successive "nose-up" flights.
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