ORIGINAL: Gry101
rjbob, sorry I forgot the particulars, just a little frustrated here.
OK, I have one 40oz tank. However, each motor has its very own fuel pick-up. There is one vent line and one fill line, though I think that should not matter. The tank is around 12 inches away from the engines themselves and the pumps draw the fuel through fine after a little priming. Thank you for the fast response.
just a thought, but maybe the single vent line isn't up to the task, and when both engines are running they are beginning to suck the tank in a bit and cause one to run lean and quit? Maybe try a larger size vent tubing system than the fuel supply system.