Need Help 24' Superboat
 

I just bought a 2000 24' Stepbottom Superboat with a 225 mercury promax just rebuilt new pistons and cranks and new lower unit.

I took it out for the first time today and something is wrong because with myself and 4 others our max speed was 43(GPS).
The boat had 30gallons of gas in it and I would think we would reach about 60mph. The racing unit was replaced by a non-racing lower unit(talked to John coen and he said this shouldnt change the speed). The rebuilt motor has about 2 hours currently on it.

Anyone have any idea what's wrong?

You failed to mention prop & rpm @ wot
Does it come out of the hole strong & bang rev limiter?
If the motor runs good, I'd bet the prev owner just slapped a junk or under sized prop on after replacing the lower to save a couple $ or keep his $$$ wheel.

about 6500rpm at wot and spinning a Michigan wheel Apollo xhs A series. is that a bad prop or...?

You need to find pitch. (# stamped on prop ) & find a 24 7 sob guy.
Maybe pm rcchevelle he has a sob pantera.

I'd bet the guys here http://www.screamandfly.com/forumdis...ing-Discussion
know whats going on with your boat.

prop pitch is 14x22 and ok mad ill check that out

Too small. Try a 25 or bigger

alright i'll try one out

Like I suggested...pm rcchevelle. Rick has a 200 on similar hull ( non stepped ) so he may be able to offer you a baseline , or comparison . But imo a 22 is way low & sounds like ya prob.

His straight bottom 24 with a 200 merc is just above 60 I believe

Good luck

EDIT..... I thought these motors had 1.65 lowers, did research turns out they are 1.75 & a 25 pitch may be a bit ambitious.....either way I'd start playing with wheels & prop height.

200:lolhit:

Nah, I run a 250EFI now. Previous motor was a 225 merc 25" carb fishing motor, and the boat ran high 50's consistently, 59.8 on a good ay with the 225. Something is definitely not right nere, he has a step, a motor setup to turn more RPM, most likely a lighter hull than a Pantera, and runs 15ish miles an hour slower than I did with a tired fishing motor. First palce I would look at is prop, but right now I run 55 with a 19 pitch 4 blade at 6000 RPM, or 60+ with the 21 3 blade at 5400, I find it hard to believe that prop is that bad? Props are somewhat cheap though and readily available to borrow. My choices for that motor would be a 23 Mirage Plus for all around speed/handling, 23 Tempest for speed, or a 23 trophy plus 4 blade for handling.