Hello evryone . Y bought a boat last summer .
fountain fever 27 1992

engine was supossed to be a bullet 540 650HP

bloc is a merlin III whit Merlin IV cast iron head .

me question is what the rpm range ?

i run a 28p on bravo XR sportmaster 1.50 whit steeling extension box . Run 5000rpm at 70mph … it realy slow …

If it’s making 650hp it’s probably making it at 6k. Just a guess but with that said even if you dropped down a couple of prop sizes I wouldn’t think you’d gain much speed. Maybe a couple mph at best but would likely respond better! Have you cked the transom and stringers for moisture? A good friend and member had a 565 790ish hp that ran just shy of a 100 and around the same year as yours. Details are distant past however Rookie will have the particulars as valako doesn’t frequent here much!

Yes i tried a 26p lab finish , y get about 2-3mph and 5200rpm .

Id be surprised if you are getting the power they sold you on. I have a 29 fever with a 525EFI and an XR drive and can turn a 28p Bravo to 5250.. I would imagine if you were making that sort of power you would be blowing out a 28p. I'm not sure what the extension box will do to my equation here, but feel like you aren't seeing the power you should.

What type of 26 lab did you put on there? Was it a Bravo as well?

Is your sportmaster lower standard length ?

Perf125,

We are running a 28P Bravo prop on a 1.5 Bravo1 drive, and we are running 77-78 at 5000RPM. Check to make sure the prop is stock.

Thanks. Brad.

we run a 25 footer 540 with cast iron ported heads and big valve springs solid roller bullet cam bravo xr stock bravo 26 we can run a bit over 100 and can turn it up to 7000 rpm is your friend...to much torque is not

Sorry im not very good in english . The guy sold me the boat say me it have no information about the engine . But when im look how it’s rigged it’s look similar too the bullet engine . I took out the engine too send it on the dyno .

but a fountain fever whit 540cubic inch engine do 70mph it realy slow …

for the extension box is a Steeling 13inch . The drive shaft between engine and box its on very angle … i think y losse power here …

The drive lower is a standard leght .. im good mechanical but i dont realy good whit the X dimension end the drive height … the boat was hard too place on calm water when y hit full throtel …

And a grin to watch and here it turn those R’s. 😂
I love it but many don’t.

That’s 26 AT right? Bro how drive you grenade? 🧐

Double post