User Manual

ManualsBrandsO.S. Engines ManualsEnginesFS120III Pump Ring 70N Carb

Start and adjust the engine as detailed in the starting

instructions.

Now open the throttle fully and run the engine for no more

than 5 seconds with the needle-valve tuned to produce near

maximum r.p.m., then, immediately, slow the engine down

again by opening the needle-valve approximately one turn.

The rich mixture, so induced, will cool the engine, at the

same time providing increased of lubrication.

Allow the engine to run like this for about 10 seconds, then

close the needle-valve again to speed it up to near

maximum rpm for another 5 seconds.

Repeat this process, alternately running the engine fast and

slow by means of the needle-valve, while keeping the

throttle fully open, then begin to extend the short periods of

high-speed operation until two full tanks of fuel have been

consumed.

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.

WARNING:

When ground running the engine, avoid dusty or sandy

locations. If dust or grit is drawn into the engine, this

can have a ruinous effect, drastically shortening

engine life in a matter of minutes.

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 to enable the

needle-valve to be readjusted to a richer setting.

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. 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.