O.S. Engines FS-52S - Manual (Page 17)

Following the initial running-in session, check for
any looseness in the installation due to vibration,
then allow the engine a period of moderately rich
operation in flight.
For the first flight, have the needle-valve set on the
rich side and adjust the throttle trim on the
transmitter so that the engine does not stop when
the throttle is closed to the idling setting.
5.
6.
RUNNING-IN (continued)
With each successive flight, close the needle-valve
very slightly until, at the end of about 10 flights, the
needle is set for full power. Do not "over-lean" the
mixture in an attempt to extract more power.
If overheating should be suspected at any time
during flight (i.e.if the engine begins to labor)
reduce power by partially closing the throttle and
land the aircraft and reset the needle valve for a
richer setting.
7.
8.
Once the engine has demonstrated that it can be
safely operated at full power, the carburettor can
be adjusted for optimum throttle response,
following the instructions given in the next section.
Note:
Remember that, when the engine is not yet fully
run-in, the carburettor cannot be expected to give
its best response in flight. Abrupt operation of the
throttle, for example, may cause the engine to
stall.
9.
Therefore, at this time ,the aircraft should, as far
as is possible, be flown at an altitude sufficient to
enable an emergency landing to be safely made if
the engine stops.
Start the engine, open the throttle fully and set the
needle-valve slightly rich (30-45
°
) from the highest
r.p.m. setting.
Close the throttle to the idling position. Allow the
engine to idle for about 5 seconds, then reopen the
throttle. The engine should accelerate smoothly
back to full speed.
If, instead, the engine responds sluggishly and
emits an excess of white smoke from the exhaust,
the idling mixture is too rich. Turn the mixture
control screw approx. 45
°
clockwise to lean the
idling mixture.
IDLING MIXTURE ADJUSTMENT
1.
2.
3.
16