You might check for retained water in "dry" spacees or waterlogged
floatation. I have seen that more than once, especially in older boats.

C.F.

bruce wrote:

I have a 15 1/2 ft fiberglass trihull with a 65 hp merc.
Once the boat gets on plane it goes about 26 mph, which seems ok to me, but
it takes forever to get up on plane. I have played with the manual trim,
with no change.
I have to move people around in the boat until it starts to pick up speed
and takes off.
One other thing, it seems to burn gas like a torch.
The numbers on the prop are
48 85632 A40L 11P

Any suggestions?