sounds like fuel starvation. remove fuel filter from tank and replace. if its an old model, may need carby overhaul.
screw hi and low mix jets in gently until stops, screw both out one turn. screw idle jet in also..start, screw low screw out a bit at a time until motor runs without choke. however, you will need to screw in idle screw in to ofset the lower revs.
mike brooker. australia, August 2007
