What kind of fuel are you burning. I was using wild cat for the first gallon ( YUCK!) and had the needle valve out 4 turns to get some smoke. Since switching to cool power 30% im out almost 2 turns. So maybee try changing fuels.

Also when I was flying planes i would sometimes have a controlled crash, and would get some dirt and junk in the carb that would totally screw up any setting I would try to do.

I hope that helps.