If your motor stutters in lower rpms, chokes or stops, you can adjust the mix with the pilot mixture screw. Screw it in, the mix is leaner, screw it out and the mix is richer. The optimal value should be about 0,5 to 2,5 turns out of the housing. For example, if you need 4 turns, choose a smaller idle mixture jet. It’s marked with two numbers. For example, 50/120. You can find out the right size by dividing the second number by the first; in this case it would be 2,4. Further, with these jets the motor runs richer the smaller the value of the jet. To the right is a list of available jets.