1995 YZ 250 fouling plugs?

ok so I foul plugs, and I HATE it and really don't wanna bring it to the local junkie bike mechanic, I understand that if I'm running rich on my air/fuel ratio too much gas/oil will build up and it wont ignite it and mixed with riding slow will cause the engine to run at lower temperatures so its not hot enough to burn the stuff off the spark plug all eventually causing the plug to fail and leaving me on a back road somewhere --_-- its a keihin carb, main jet 175 pilot 48, pretty sure the airscrew is suppose to be at 1 1/2 with a pro circuit (which I have) don't I just have to turn the airscrew 1/4 turns counter clockwise and see how she runs? wont it also run better if my air/fuel ratio was out of wack? I'm just slightly intimidated by the carb and jetting mystery....