Every engine is differnt, but the following instruction should get you close-> I'm assuming we're talking about your high and low speed settings, and the engine has already been borken in correctly...

1) Turn the screw/knobs clockwise untill they bottom out. Dont over tighten, or you can damage you engine.
2) Now back the setting out 2 turns counter clockwise. This should get you close. My instructions say 2 1/2 turn, but its better to be over rich than over lean.
3) now just tune the engine settings until you satisfied with the performance.
4) reapeat for other engine settings....

AGAIN EVERY ENGINE IS DIFFERENT