If you can adjust the low speed mixture while running...turn the screw leaner(clockwise) until the engine starts to slow down, then turn the needle counter clockwiseuntil it speeds up and keep turning until engine begins to slow down. Notice the position of each point and set at a point 1/2 way between. That should be close. If when you open the throttle the engine has a big hesitation...turn the needle out to richen it again until the engine revs up without hesitation. Do this after the engine is warmed up. Capt,n