Chris have you pulled your pump and replaced them ?? I have never done it, Lance at F&S may have at some point.. I change out all the one's I can get to regularly, and I added a water seperator w 20 bizillion micron filter. Hopefully I can catch any bad stuff before it gets that far, been ok for 13 yrs..
To the OP,
I had some old/ bad gas cause mine to stumble on higher rpm's, it didn't take long to go bad.. Chuck at service marine said it lose's octane power quickly, he gave me a pump to sux it all out, and into my truck. Ran fine in the truck's hemi.. Justsay'n
New plugs, and fresh gas, boat runs like a scalded dog...