I bought a boat with a 2004 Optimax 135 this past December in Minnesota (it was being stored in a heated shop), hooked it up at the dealership, ran it for awhile on muffs, hooked it up to the diagnostic computer, all was good. Motor has 119 hours of run time on it, all but about 20 hours was at idle.

It was stored all winter long with an empty gas tank with quickleen treatment in my garage which stays about 40 degrees, but does get pretty damp, as it's a tuck under garage. I filled the tank last weekend and took it out, it ran great at idle and even on plane at lower rpm's, but after running for 3-4 minutes at WOT the motor would cut out for a split second, then keep going, then cut out again for a split second, etc. IT would run perfectly smooth again at lower RPM's, but when I'd get back up to WOT it would do the same thing.

Is it possible that I have water in my gas from sitting with an empty tank all winter? Any suggestions on other things I should check?