GM-Racing 90161.RTR Bedienungsanleitung Seite 12

WHAT DOES „RICH" AND „LEAN" MIXTURE MEAN?
Adjusting the carburetor is one of the most critical things when driving fuel powered RC cars. It refers to the
mixing ratio as „rich" when too much fuel in proportion of air gets in the carburetor, and as a „lean" with low
fuel in comparison with air. The fuel portion is set with the high-speed and low-speed adjustment screws. The
low-speed screw is located on the front carburetor rotary valve. The high-speed needle stands bolt upright on
the back of carburator. If you rotate the screws in clockwise direction, the mixture is getting lean and vice ver-
sa. A pronounced „rich" mixture shows slowly acceleration and less performance with thick smoke from the
exhaust. In „lean" mixture the engine can „swallow" before then rev up suddenly, or maybe, after a short in-
itial acceleration slowdown in the performance. A lean mixture leads to undesirably high engine temperature
and reduces the lubrication of the engine parts inside, leading to excessive wear and damage. It is always
advisable to run the engine slightly rich and never lean to avoid overheating and possible damage.
MOTOR TUNING
If the engine is run-in, you can use it to maximum performance. It is important that you
carefully watch the engine temperature, overheating cause serious damage and exces-
sive wear. Make any changes to the carburetor screws in the 1-hour increments (see
fi gure).
Caution: Warm up your engine before making adjustments on the carburator set-
screws!
LOW SPEED NEEDLE ADJUSTMENT
The low-speed setting affects the performance of idle and slightly higher. The optimum setting is when the
engine runs for at least 8-10 seconds in idle, then, the vehicle then should accelerate with a slight amount of
sluggishness and a noticeable amount of smoke. The simplest way to check this, after the engine is warmed
up, let the engine run in idle for about 8-10 seconds. If the idle mixture is adjusted so that the engine is not
running so long, turn the idle screw clockwise to increase the idle speed. While the engine rotates in idle, pinch
now the fuel line close to the carburetor to interrupt the fuel supply, and listen to the
engine speed. If the low-speed needle is set properly, the engine speed will incre-
ase only slightly, and then die. If the speed before dieing increases several hundred
revolutions and remains there, the low-speed is too rich. If the engine speed not
accelerates, but rather simply dies immediately, the setting is too lean and must be
set by the screw an hour in direction "rich". If the low-speed needle is optimally set,
the engine is idling probably in a little bit higher RPM. Then you have to adjust the
idle set-screw counterclockwise to reduce the idle speed of the engine. The engine
must rev up with constant acceleration and run without breaks or delays.
HIGH-SPEED NEEDLE ADJUSTMENT
After initial spin of the motor must rotate evenly and the typical two-stroke howling with clearly identifi able
smoke plume. If the engine tortures and heavy smoke plume dropouts shows that the mixture of rich and
lean must be set by the high-speed needle setscrew in 1-hour increments „clockwise" until the engine runs
quietly. If there is no smoke to see the mix is too lean and you need to adjust the mixture by turning the screw
counter-clockwise. Don´t be confused by the sound of the engine and the actual
performance. A lean mixture generates a higher exhaust noise, but that does not
necessarily mean higher performance, because the engine is close to overheat.
Ideally, you should run the engine so that it is based on the rich side. The result is
the best mix of speed and life expectancy of the engine.
Caution: The mixture is too lean and the engine is running hot when accelerating
quickly and with a sharp noise, then runs hard, showing no longer smoke or the
speed reduces. This can be caused by the terrain characteristics, atmospheric con-
ditions or drastic height differences. To prevent permanent damage to the engine,
you must then immediately enrich the mixture by turning the high-speed needle
screw at least two hours steps in „counter-clockwise" direction, and be prepared for
further adjustments made before you continue driving.
11 GM-Racing 90161.RTR Monster Truck MT8 Nitro
Montage Servo - Stoßdämpfer
Servo set - Shock Assembly
GM-Racing 90161.RTR Monster Truck MT8 Nitro 20