RollWithIt

A customer of mine at my marina has a crownline with the Bravo 3 Duoprop. He has recently had the engine rebuilt and is looking to see what is available for higher performance props over the original props. I dont know the pitch or size off hand. But am curious if there are any aftermarket props out there for the Bravo 3 drive. Or is his best bet going to be getting his current props labbed? Thanks for any information.

throttleup

Unfortunately, there are no other options available to your customer for the BIII props. It really depends on what motor mods were performed but, he may need to re-work his props or possibly purchase new props . We really need more information to help you more specifically.

Julie

SeaRay Jim

I have pictures of what BIII props do when you try to make a BIII a performance drive. After labbing my 30p's, first trip out and I can see slight traces of burns.

I'd say this, if they are turning anywhere near 5000 engine RPM (2:1 gear) and pushing near or over 60 MPH I can almost gaurentee they will be burning props up especially if they are turning high pitch like 28 or 30's. I'm a permanant 30p BIII shopper so that I have spares.

I may try a nose cone next. My unprofessional opinion, based on real life cases only, is that the BIII's hydrodynamic effeciancy is gone once you start turnning the props 2400 RPM or more and are at speeds in the upper 50's and up. The only boat I know of that met both criteria that did not burn props up had/has a nose cone.

BTW, that boat is a Crownline 225 with a Whippled 502 Mag turning labbed (lots of cup) 30's and 1:81 gears.

bbladesprops

OK, you guys are missing something.

In 2003 Mercury Racing began redesigning the Bravo 3 propellers. The reason is broken down in a long post I made many months ago on this board.

I remember it like yesterday. I was still at Merc Racing when we started mating 500 EFI's to Bravo 3 drives on sport cruisers. We would burn though (literally) a set of B3 props in 7 hours. The process took some time but there is currently a new offering of B3 XR propellers available from Mercury Racing! The set comes with a 4 blade front and a 3 blade rear.

We just Lab Finished a set at BBLADES for a 2005 38' Fountain with great success.

So yes there is a alternative!!

throttleup

Here is the link.

http://www.mercuryracing.com/product...avothreexr.php

JUlie

evaluex

Only available for B3 XR drives or also "regular" B3 drives ??

bbladesprops

Either.

SeaRay Jim

Guess it depends on what size you need. Appearently the largest pitch available in the new XR's is a 27 (used where standard 28's would be). I'd need to regear, or turn the 27's up above the RPM range I need too, unless they could be worked to bring RPM's down.

S4Hadi

I'll testing the high performance BravoIII this season .

I repowered my '98 Formula 252LS, 4500lbs weight according to a brochure and it has a 22 degree non step bottom.

I upgraded from a 502 MAG MPI 415HP to a HP525 (500-525HP's) mated to a BravoIII 2.0 R.

The boat went from turning a balanced 28"P's duo prop at 5100RPM's to 5200RPM's on a re-pitched & cupped 30.5"P's.

No speed readings as my speedometer is not working , but it only indicated to 65MPH's which I was pegging with the 502MAG already

I can feel the extra power via g-force acceleration and WOT speeds....need a GPS badly

My questions are:

1) Should I have my spare 28"P's repitched to 29"-30"P's to bring the WOT closer to the 5450RPM rev limiter? That woud also slow the at idle cruise speed down a bit.

2) Will I have a problem with the props? I thought that the BravoIII would be the weak link?

3) Is there an alignment procedure when installing the two 3 blades on top of each other or do they turn independently of each other?

Thanks,

Jamal

SeaRay Jim

I'd be interested to know how your does. It's very similar to mine.

My guess is that you'll burn the props up, but who knows.

As for installing the props, they should look like a clover leaf. I line up the front prop with one blade dead center of the cav plate, then stagger the rear prop so that 2 blades are straddling the 1 front prop blade. You just want to make sure that 2 blades don't cross under the cav plate. If you're 1 spline off, you will see it as you turn the props. Mine would blow out quickly (splat splat splat) being 1 spline off. Corrected it and the splat splat splat went away.

Are you props plolished or satin finished? I'm curious if a polished finish will resist cav burn better.