Jens-Erik

You should be getting more RPM's out of the boat. Two things I would
look for. First, I would remove the distributer cap and make sure the
advance isn't stuck, holding the rotor you should be able to rotate it
freely about a quater turn in one direction, and it should snap back
when you let go. If that's stuck some silicone spray should help free
it up. The next thing I would look for is the secondaries on the carb,
if it's a four barrel carb. With the engine off place the throttle at
full throttle. The secondaries operate by either mechanical or vaccume
action. The mechanical linkage should move freely, if it's mechanical.
If it's a Holly carb it has vaccume secondaries, again, make sure
everything moves freely, if it does you may need to repair the vaccume
secondaries (it's easy, just get the part and replace it). Also, make
sure that little hose going to the vaccume actuator isn't leaking.