Well I got my engine running and idling well. On the hose in the driveway everything is perfect, can rev up to 3500 and timing advances, running at 2000 rpm sounds perfect. Idles at 550-600 rpm<br /><br />Dropped it in the water for the first time and up to about 2000 rpm everything sounds great while underway, right at 2000 rpm I get backfire through the carb. If I back it back down to 1200-1500 it goes away.<br /><br />Any suggestions?