I installed a T in the fuel outlet line with ball valves to periodically blow back into the tank to clear the crud from the bottom. I have drained and flushed the tank but still cannot seem to get all the crud out. Blowing back into the tank with air while the machine is leaning to the right seems to get me through the season. Also after blowing back I leave the machine sit overnight so the crud settles away from the tank sump. Pete Hinrichsen