11. What is a good initial setting for the idle mixture and the adjustable main jet?

Our recommendation for the initial setting of the idle mixture is to turn the needle in against the seat, and then back it out one turn from the seat. After the engine warms up, the adjustment should be fine-tuned to the point where the engine idles most smoothly.

For adjustable main jets, there is quite a comfortable range of initial settings, ranging from one to two complete turns off the seat. The adjustment should reset for the best RPM at your favorite cruising power setting with the engine fully warmed up.

Remember that in the case of the idle mixture you are controlling the air, so turning the valve in (clockwise) reduces the air and hence makes the mixture richer. In the case of adjustable main jets, you are controlling the fuel, so turning the "T" handle in (clockwise) reduces the fuel and makes the mixture more lean. - Updated: November 4, 2003