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Stage 3: Setting the Low-speed Needle
Open the carburetor for 2-3 seconds and let the engine clean out. Close the carburetor and
let the engine idle.
• If the engine idles for 2-5 seconds and then the idle RPM decreases, the engine is
running too rich during idle. Lean the low speed needle (clockwise) to remedy this
condition. Repeat this step until the engine idles reliably at a constant RPM for at least
20-30 seconds after the carburetor has been opened for 2-3 seconds.
• If the engine idles for 2-5 seconds and then the idle RPM increases, the engine is
running too lean during idle. Richen the low speed needle (counter-clockwise) to
remedy this situation.
• If the engine will not idle at all, rich the low speed needle (counter-clockwise), or turn
the idle adjustment screw clockwise to increase the idle RPM.
NOTE
: Because adjusting the low speed needle affects the idle RPM, use the idle adjustment screw to get the engine to idle
at the right RPM.
Once you are satisfied that you have achieved reliable carburetor settings, you are ready to put your car on the track.
Stage 2: Setting the Idle Speed
Take the car off the ground, and open the throttle fully for 2-3 seconds. Close the carburetor
and check the idle speed that occurs immediately after.
• If the engine stops almost immediately, turn the idle adjustment screw clockwise to
increase the idle RPM.
• If the idle RPM is too high, turn the idle adjustment screw counter-clockwise to reduce
the idle RPM.
Adjust idle speed RPM
Adjust low-speed needle
Summary of Contents for NT18 0.8cc
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