Guys,

when I advance the throttle after extended down lines (when the throttle was at idle) the engine hesitates and sounds like it's going to quit before it "spools up" again. It always sounds like it's going to quit, but never has - just kinda unnerving.

My needles are set so at full-throttle it runs perfectly and at half-throttle or a little below it burbbles/four-strokes (if that has anything to do with it which I don't think it does).

Any suggestions?