502 MPI port engine
 

wont stay running. It starts and runs sometimes, but today it idled and died after about 100ft down channel. With a prospect buyer aboard! Ive only had the boat out once on memorial day. It wouldnt start so they left and 10 min later it started up. It spuddered for about 25sec. and now seems fine. I'm thinking water in the fuel or something, never had any problems until I let it sit for so long.

I would think that if there was water in your fuel, it would get into both engines. I would put a scanner on that motor and see what it tells you. You may have a code stored that can help pinpoint the problem.

Has anyone tryed the 2cycle oil in the fuel filter and run till dry thing for long term storage?

It was the electric fuel pump, all is fine now.