I have a 1991 27' Fountain Fever. No step. 502 mag, bravo one, 1.36 ratio

Current prop is a 19" powertech 3 blade prop. Today, empty w/ almost no gas i got 60 mph at 5200 RPM. With a borrowed 23" Mirage plus, i got 61.4 mph out of it, but only at about 4400 rpm. The 23" prop was too much to get out of the hole with too many people aboard.

I'd like to pick up a few mph at WOT but i'd rather pick up speed in the midrange and plane better. I don't know if i should run a 20 or 22 inch 4 blade prop or a 21 inch 3 blade. And i don't know what brand would be best.

What do you guys suggest i get?

Depending on the diameter of the Power Tech you will need a propeller that is about the same pitch in a 4B. This will bring your RPM down. Your gear ratio is putting you in the smaller pitch propellers. As you increase pitch you decerease RPM so the 20 or 22P props will bring your RPM down most likely. You need to run your motor at 5000 RPM at WOT.

Julie

Well it looks like i'll be trying a 21" mirage plus. That's what i found used.

My buddies 27 w/ a 496 ho runs a 24 pitch Bravo 1 at 68/69 mph at 5000 rpm. You should be able to at minimun turn a 22 pitch Bravo 1, maybe a labbed 24 pitch would work perfect for you.

That's what i thought, too, with a fresh 502. I do have a 1.36 ratio drive though. When i tried a 23, i picked up speed despite dropping down to 4200-4400 RPM.

We'll see what the 21 does for me. With reasonable slip i should be able to run 65 with it, if i'm making enough power to turn it. 65 is about what i figure the boat should run.

look at his gear ratio 1.36:1

your buddy is probably running a 1.5:1