Help it's Sputtering!!

[CapeBoater1]

Ok, first trip was great and my motor ran flawlessly. Second short trip it was sputtering a bit at slow speeds. It was almost like it would skip a bit with a slight lurch forward (ever so slight). I went out fishing today and it was sputtering a bit about an hour after I left and when I accelerated, I noticed it sputtering and It would not throttle up fully. I could only get around 3000 rpms when I was getting aroun 4200 on the way out. Water pump seems to be spitting enought water so I don't think it's overheating. Could it just be old fuel, or maybe the inline fuel filter? It's a 1988 force 125 in case anyone has one.