I bought a 25-year old Evinrude 2HP, with an integral fuel tank on the top of the motor. It's a gravity feed fuel delivery (no fuel pump), so the only force delivering fuel to the cylinder is gravity and the vacuum of the cylinder rising pulling fuel Into the crankcase thru the carb. Runs great at idle and up to about 2/3 throttle, but when set to WOT, the motor stalls after running for a couple minutes. I've rebuilt the carb (twice), decarbed the motor, replaced plug and checked gap (.030), checked spark strength (jumps nearly 1/2"). Copmpression is good (110). The prior owner installed a non-standard in-line fuel filter in the fuel line between the tank and carb. The filter bowl is a clear see-thru, and I've noticed that when running it's maybe 1/2 full with fuel, no more, even though the syphon effect would say it should be full. Seemed to run better (but still not at WOT) when I replaced the filter with a straight fuel hose while de-carbing. Could the slight additional resistance to the fuel flow of this non-standard filter be the problem? (I suppose I could just replace the filter with straight hose again, but the motor's down at the boat a half hour away, and I'm thinking of it now, I knew some of you guys would have experience with this.)
