11
Testing the Temperature
The ideal operating temperature for the engine will vary with
the air temperature and altitude. In general it should be in
the 190° to 230° F (88° to 110° C) range. The telemetry on
you transmitter will display the temperature as long as the
temperature sensor is attached to the engine. Please note that
the location of the sensor will also make the readout vary a
little. If the engine is overheating turn the high-speed needle
out (counterclockwise) at least two hours as shown in the
“Tuning a Nitro Engine” section. If the engine is running too rich
(below 180° F) turn the high-speed needle in (clockwise) one
hour at a time until it is running within the normal range.
High-Speed Adjustment
After initial acceleration, the engine should pull at a steady rate
while maintaining a two-stroke whine and a noticeable trail of
smoke. If the engine labors and is sluggish with heavy smoke,
the mixture is too rich and needs to be leaned by turning the
high-speed needle clockwise in one-hour increments until it
runs smoothly. If the engine isn’t smoking or starts to die after
acceleration, it is too lean and you must richen the mixture by
turning the needle counterclockwise. Don’t be confused by
the sound of the engine and the actual performance. A leaner
mixture will produce an exhaust note with a higher pitch but
this does not necessarily mean improved performance, as the
engine is on the verge of overheating and may incur possible
damage. Ideally you want to run the engine so that it is on
the slightly rich side of optimum. This will give you the best
combination of speed and engine life.
CAUTION
: The engine
is too lean and overheating if it accelerates rapidly with a
high-pitched scream then seems to labor, stops smoking, or
loses speed. This can be caused by the terrain, atmospheric
conditions, or drastic altitude changes. To avoid permanent
engine damage,
immediately
richen the mixture by turning
the high-speed needle counterclockwise at least “two hours”
and be prepared for further adjustments before running any
more.
Note
: The normal operating temperature as seen on
your radio screen should be in the 190 to 220° F (88 to 105° C)
range.
About Glow Plugs
The glow plug is like the ignition system in your automobile.
The coiled element in the center of the plug glows red hot
when power is applied to it. This is what ignites the fuel/air
mixture when compressed in the cylinder. After the engine
fires, the heat generated by the burning fuel keeps the element
hot. Common reasons for the engine not starting are the glow
plug being wet with fuel low voltage in the battery or the
element is burned out. Disconnect the igniter lead from the
glow plug in the engine and connect it to a spare plug holding
it up against the head or engine case so it is grounded. Press
the starting button and if the plug glows you know that the
plug in the engine is bad and needs to be replaced. A wet glow
plug means there is excess fuel in the engine. To clear this pick
up the model by the wing letting the front end hang down.
Open the throttle all the way and try starting the engine for 2 or
3 seconds. If it does not fire, stop and wait for at least 5 seconds
and try again. If it does start to fire, close the throttle then pull
the trigger 1/4-inch and continue to turn it over until it starts
and clears out. Release the trigger so the engine idles, place it
on the ground and start driving.