O.S. Engines 21TM - Manual (Page 10)

18
Remember!
It is vitally important to set
the throttle at the correct
position before attempting
to start the engine. If the
engine is allowed to run
with the throttle too far
open under "no load"
conditions, it will rapidly
overheat and may be
seriously damaged.
When the engine starts, first allow it to operate
in short runs on its very rich starting settings,
with the glowplug battery still connected and
with its driving wheels clear of the ground. The
rich mixture will, under these conditions,
provide adequate lubrication and cooling,
indicated by profuse smoke from the exhaust.
Next, disconnect the glowplug battery and try
running the car on the track. If the engine
stalls, open the throttle fractionally, but try to
keep the engine running as rich as possible: if
it stops because of being excessively over-
rich, close the Needle-Valve 30˚ and try
again.
Run the car on the track until one tank of fuel has
been consumed, then close the Needle-Valve
30˚. Repeat this procedure again until five tanks
of fuel have been consumed, during which time
the throttle may be opened for brief bursts of
increased power. If the engine stops at medium
speeds, close the Mixture Control Valve 30˚. The carburetor on this engine has been set at
the starting setting when the engine leaves the
factory.
Switch on the transmitter, and check that all the
linkage moves correctly.
30˚
Needle
The position of the needle-valve
when starting the engine.
Close the needle-valve approx.
30˚ after running the vehicle for
every one full tanks of fuel.
Repeat this procedure around
five times.
30˚
30˚
19
Note:
If the engine should need to be disassem-
bled (e.g. for cleaning or minor parts re-
placement), it is advisable to return the nee-
dle-valve to the original rich, starting set-
ting and check whether further running-in
time is required before the car is raced
again. In the event of any major working
parts (e.g. piston/cylinder liner assembly)
being replaced or the fuel being changed,
especially to high nitro fuel, the complete
running-in should be repeated.
Fuel
Warning!
Do not touch rotating parts, engine and si-
lencer when stopping the engine as they
become very hot, and contact with them
may result in a serious burn.
To stop the engine, close the throttle to idle
speed, then shut it off completely with the
trim lever on the transmitter.
To cut off the fuel supply,
pinch the fuel delivery tube
to the carburetor.