Too lean engine movie
http://www.traxxas.com/support/movies/lean.mov
Any of the above symptoms indicate that the fuel mixture is past maximum safe lean setting. Turn the mixture screw back out (counter-clockwise) the previous 15-degrees to reach the optimum fuel mixture setting. Turn the mixture screw out another 15-degrees for non-race applications. This will extend engine component life. This setting will vary slightly with each engine depending upon fuel brand, temperature, humidity, etc.
FINE TUNING THE LOW SPEED MIXTURE
The low-speed mixture screw is located in the end of the throttle shaft. The low speed mixture affects the idle quality and the low end engine power and throttle response. To check your low speed mixture setting, perform this simple test.
1) Drive the vehicle for several minutes until the engine is in its normal operating temperature range.
2) Pull it in, stop, and listen to the idle speed. If, after a few seconds, the idle speed begins to drop then lean the low speed mixture 1/8 of a turn (clockwise) and retest.
3) Continue leaning the engine in small steps until the idle speed will stay even for at least 20-30 seconds after stopping.
4) The vehicle should accelerate quickly from a standing start without bogging. The idle should be smooth and consistent. Lean the mixture 1/8 of a turn (clockwise) and re-test. If you experience any stalling or hesitation when accelerating, then the low speed mixture is too lean. Richen it 1/8 of a turn (counter clockwise) and retest.
Second test
Pinch the fuel line to the carburetor and observe how long it takes for the engine to stall. If the engine stalls immediately, then the low speed needle is probably set too lean. You should be able to pinch the fuel line for 1 or 2 seconds without stalling the engine. You should also hear the engine speed up just before it stalls.
SETTING THE IDLE SPEED
Now that the engine mixture is tuned, the idle speed may be set too high. If the model moves forward at idle, reset the idle speed by removing the air filter and adjusting the idle speed screw on the side of the carburetor, turn the screw clockwise to increase idle speed, counter-clockwise to reduce idle speed. Turn the screw out (counter-clockwise) until the engine will idle consistently (without stalling) and the model will sit still without any brake being applied. If you are having to constantly blip the throttle to keep the engine from stalling, then the idle speed is set too low. |
