If you still have the problem after trying to readjust it as Campy suggested, take the needle valve out and flush fuel through the carb and clean the needle off good the reinstall and go through the adjustment Campy uses. By the way when reinstalling the the needle valve I usually turn it in till it JUST touches bottom then turn it out 1 1/2 turns and it normally starts so I can do the adjustments. ENJOY!!!!