Generally, the air screw adjustment should be out between 1 and 2 turns. You do this by setting your idle, then adjusting the air screw for optimum idle. Then readjust idle screw to lower idle back to optimum idle speed. (usually around 1,100 - 1,400 rpm IF memory serves me correctly--and sometimes it doesn't). If air screw is backed out more than 2 turns, it is too much and your pilot jet is likely too large.
But I don't think that is your main problem. I think more likely cleaning of the carb and changing the needle position is what you need. A one position change of the needle can make a huge difference.