O.S. engine MAX-32SX Owner's Instruction Manual page 19

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.
Re-start and adjust the needle-valve so that the
3.
engine just breaks into "two-cycle" from "four-
cycle" operation, then make three or four flights,
avoiding successive "nose-up" flights.
4. During subsequent flights, the needle-valve can be
gradually closed to give more power.
However, if the engine shows signs of running too
lean, the next flight should be set rich. After a total
of ten to fifteen flights, the engine should run
continuously, on its optimum needle-valve setting,
without loss of power as it warms up.
5.
After the completion of the running-in adjust the
carburetor at optimum setting referring to
MIXTURE CONTROL VALVE ADJUSTMENT
section and SUBSEQUENT READJUSTMENT
section.
Optimum needle setting(1)
Slowly advance the throttle to its fully open position,
then gradually close the needle-valve until the
exhaust note begins to change. (4-cycle to 2-cycle)
At this point, disconnect the battery from the
glowplug, taking care that the battery leads or
glowplug clip do not come into contact with the
rotating propeller. If the engine stops when the
battery is disconnected, close the needle-valve about
30˚ and restart.
Optimum needle setting(2)
As the needle-valve is closed slowly and gradually,
the engine r.p.m. will increase and a continuous high-
pitched exhaust note, only, will be heard. Close the
needle-valve 10-15˚ and wait for the change of r.p.m.
After the engine r.p.m. increases turn the needle-
valve another 10- 15˚ and wait for the next change of
r.p.m. As the speed of the engine does not instantly
change with needle-valve readjustment, small move-
ments, with pauses between, are necessary to arrive
at the optimum setting.
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