28
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.
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 idle
setting.
8.
6.
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.
7.
29
IDLE MIXTURE ADJUSTMENT
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 idle 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 idle mixture is too rich. Turn
the mixture control valve approx. 45
°
clockwise to lean the idle mixture.
On the other hand, if the engine hesitates
before picking up speed or even ceases
firing completely, the idle mixture is likely to
be too lean. Turn the mixture control valve
90
°
counter-clockwise to substantially enrich
the mixture, then back again 45
°
clockwise.
In paragraphs 3 and 4 above, the 45
°
total
movements are, of course, approximate. It
will be necessary to fine-tune the mixture
control valve 10-15
°
at a time to reach the
best setting for optimum throttle response.
Continue re-checking the idle mixture
setting until the engine responds smoothly
and positively to operation of the throttle at
all times.
1.
2.
3.
4.
5.
6.
