2
Carburetor setup, adjust:
NGH-GT25 two-stroke gasoline engine used Walbro WT962 carburetor is designed for NGH unique. It has the perfect
stability of idle speed and acceleration sensitivity.
Always remove fuel from the carburetor after flight. Not doing so will result in rubber carburetor is components
deteriorating over time, causing loss of engine performance.
Methods: Start the engine without connecting the fuel pipe until we run out of fuel in the carburetor.
Setup Carburetor:
①—
Choke
：
Close it before the first start the engine, and quickly rotating propeller, the fuel oil suction within the tank
into the carburetor, when you start the engine should be open it.
②—
The throttle control arm
：
Infinitely adjustable-speed device, control the turning speed of the engine.
③—
Nozzle
：
Connect the oil tank and supply the fuel to engine.
④—
High speed needle.
：
After fully open the throttle control arm
②
, adjust the high speed needle can get the best
high speed.
⑤—
Idling speed needle
：
Put
②
return to the initial position, adjust the idling speed needle can obtain satisfactory
low speed.
⑥—
Idle mixture adjustment screw
：
Adjusting the fuel and air mixing ratio at idle, it actually control the initial
position of
②
, adjust
⑥
and
⑤
will obtain the better idling speed.
The initial setup of the carburetor is factory settings, the engine first start don’t need to adjust.
The factory setting status:
④—
High speed needle, Fully closed (clockwise) before exiting(anticlockwise) 1.5
～
1.75 times
；
⑤—
Idle speed needle, Fully closed (clockwise) before exiting(anticlockwise) 1.5
～
2 times
；
⑥—
Idle mixture adjustment screw, The throttle control arm at the other end of the limit pawl near the screw cone about
1.5mm.
Adjust Carburetor:
When the engine running, you want to adjust the carburetor, please adjust it based on factory Settings:
In the process of adjusting the carburetor, please use a high-quality tachometer to determine your adjusted results, the
tachometer you need to buy one.
First adjust the high speed needle: Engine run time will be turned on at full throttle position, adjust the high needle and
watch the change of the tachometer, make the engine rpm reach the max per minute. Engine work in a stable high speed
(
please note:
do not let the engine run boundary for a long time, this is a big damage for engine). Adjust the idle speed
needle: The throttle return to the idle position, adjust the idle speed needle and watch the change of the tachometer. Let
the engine run in a stable state of idle speed (Advice 16x10 wooden propeller idle speed at 1800rpm).
When necessary and idle mixture adjustment screw joint adjustments to ensure the engine idle speed stability, smooth
acceleration; If the engine is idling start difficult (Exclude CDI ignition power shortage, excessive fuel combustion
chamber, spark plug problems and so on). This shows that air-fuel ratio (A/F) is low at idling, please adjust idle mixture
adjustment screw, increase air ratio, or adjust idling needle to reduce the amount of fuel, A/F ratio to achieve
appropriate proportion. (
Tip
: The larger engine propeller, the more perfect lower idle speed you will get. )
When the engine high speed and idle speed adjustment is completed, try to run the engine acceleration performance.
First let the engine to run 10 seconds at idling and the quickly move the throttle control arm at full throttle position,
there will be the following three situations:
A. Engine speed is responsive and smooth transition to the highest speed, instructions for the adjustment of the engine is
very good.
B. Engine acceleration has a cough performance, gradually transition to the highest speed, illustrate the idle speed
needle set relatively rich oil, the idle speed needle to make a small adjustment (clockwise rotation), and then try again,
try to accelerate the reaction constant adjustment until the engine reaches your request.
C. Rapid throttle when the engine suddenly stopped running, this shows that the idle speed needle set relatively lean oil,
the idle speed needle to make a small adjustment (anticlockwise rotation), and then try again, try to accelerate the
reaction constant adjustment until the engine reaches your request.
