O.S. Engines 21RZ-R (P) - Manual (Page 14)

When the engine starts, first allow it to operate in
short runs at the very rich starting settings, with the
glowplug battery still connected and the 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.
◆ To stop the engine, close the throttle to idling
speed, then shut it off completely with the trim lever
on the transmitter. To cut off the fuel supply, pinch
the fuel delivery line to the carburetor.
Run the car on the track until one tank of fuel has
been consumed, then close the Needle-Valve 30˚
and run the car for another full tank of fuel.
Repeat this procedure until 5 more 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 Screw 45-90˚.
30˚
30˚
30˚
Needle
The position of the needle-valve
when starting the engine.
Close the needle-valve approx.
30˚ after running the vehicle for
one full tank of fuel.
Repeat this procedure several times.
•
•
• ◆ If the engine should need to be disassembled (e.g.
for cleaning or minor parts replacement) it is
advisable to return the Needle-Valve to the original
rich, starting setting 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, the
complete running-in should be repeated.
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