−11−
20〜45°
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 richer. After a total of ten to fifteen
flights, the engine should run continuously, at its optimum
needle-valve setting, without loss of power.
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.
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
revolutions of the engine will be increased 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 revolutions of the engine are increased, 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 movements,
with pauses between, are necessary to arrive at the
optimum setting.
◆
5.
Needle-valve adjustment diagram
◆
This diagram is for reference purposes only.
Actual needle positions may differ from those
shown.
To stop the engine, close the throttle completely to cut off
fuel/air supply.
Note :
•
Practical best(optimum) needle-valve setting
Exhaust note starts to change.
Disconnect battery
leads from glowplug at
about this point.
Clear, high-pitched two-stroke
exhaust note
Maximum rpm
setting("Lean").
STARTING
"Rich" needle-valve
setting when starting
the engine.
The engine may stop if
the battery leads are
disconnected from the
glowplug while the
engine is running rich.
Engine
stops
R
e
vo
lu
ti
o
n
s
s
ta
rt
t
to
d
e
c
re
a
s
e
.
to
d
e
⑥
⑦
①
②
⑤
④
③
Intermittent, high-pitched
two-stroke note
superimposed
on low "four-stroke"
sound.
Note: Although this is a two-stroke engine it fires like a
four-stroke at these rich needle-valve settings-i.e. ignition
of the fuel charge takes place at every fourth stroke of the
piston instead of at every second stroke.
〔 〕
−10−
