engine runs erratically on 2006 sporster 4-tec

[Geep]

When I put the boat in the water for the first time this year it started right up as always but soon started to sputter and almost die but not quite. I was using the fuel that over winterd but treated with Stabol. I added 5 gal. of fresh gas plus dri gas and more fuel stablizer. Proceeded to run the boat assuming it would clear itself. This has not been the case some of the time the engine runs perfectly then it will start to fade then come back. In most cases I can get it going again by changing the throtle position. As I said before it has never completely stalled out and at this point I don't think it is bad gas. Any ideas would be appreciated. Geep

 

[BMANN06]

If your getting no codes, put some new plugs in and either burn up that crappy gas or pump it out and put fresh stuff in.