Fuel water seperator

I'm thinking maybe the carb itself? If you're getting excessive dripping from the boosters, your engine might be choking on the extra gas at lower RPMs, but above a certain RPMS, can slurp down the excessive without it being noticeable.

After your start your boat and warm it up, open up the engine cover and get prepared to quickly remove the spark arrester. Then shut down the engine, remove the spark arrester, and look down the boosters of the carb. If you still have a drip, you have an internal leak.

Tell us what you find.