07-14-2009, 08:49 AM
"My motor has 620 hours. Ran great one weekend, I topped off fuel and the next weekend it stumbled, missed, surged, etc. Assuming bad fuel or water, I drained the tank, changed my water separators, (no water was found, tank was spotless), rebuilt carbs, (float setting were off by no more than 2mm), and I changed the fuel pumps last season as preventative. I tried it last weekend on the main tank (fresh fuel) and on an aux tank filled from a separate source. Tried squeezing bulb during stumbling, no effect and the bulb stays firm. No change. Any suggestions where I go next?