I'm No Expert
My buddy has a 22ft advantage with a Merc 454 Bravo 1 in it. This weekend he said that at high rpm the boat felt like it was stuttering or starving for gas. He said it would also hiccup when jumping on the throttle. He said at low speeds it seamed ok but he didnt drive it very long after this started just enough to get back on the trailer fearing that he might damange the motor. I was thinking fuel filter could be clogged or maybe some water in the gas. THe boats stored out at the river so i'm looking for as many possibilitys or things to check/look for so when i get out there i can help him diagnose it.