Mercruiser Alpha or Bravo Drive?

[dpb]

Been looking at possible future boats and finding that the ones I look at can have either drive depending on age.
This is on 24ft sports cruisers with V8 petrols.
I have had Alphas before and been happy with them, easy enough to work on and cheap as drives go to fix or replace it would seem.
Never owned Bravo hence the question.
I believe Bravos supposed to be stronger and some are duo propped.
Any comments regarding pros and cons?
Thanks

 

[MapisM]

Been looking at possible future boats and finding that the ones I look at can have either drive depending on age.
This is on 24ft sports cruisers with V8 petrols.

I would think it rather depends on the engine than on the age, but your "V8 petrol" specification is not enough.
The Alpha can handle up to a certain level of power and torque, whilst the Bravo can take more.
I would steer very clear of Alphas on big blocks - actually I don't think they are even available anymore, after Mercury learned the hard way that it was a mistake to mate them with the 454 (as they did in the past, but I can't remember which years exactly).
Otoh, if mated to small block V8s (5.0 and 5.7), Alphas are fine. Above that, Bravo is just the ticket.
Forget the duoprop version of the Bravo (aka Bravo III): that was usually installed on heavy-ish boats and/or diesel engines.
It doesn't make sense on a 24' sport cruiser, and only adds one more thing that could break, with no real advantages.

 

[dpb]

Thanks for that, it would be on a small block.

The ones I am looking at seem to all have Bravo 3's after about 2001 though (Sea Ray 240 da).
I have come across a few references to corroding drives with the B3's.
Agree about having a single prop drive to keep things simple!
There is quite a difference between Alpha part prices and those of Bravos it would seem.

 

[steve930]

I think the biggest change was that mercraiser used clutch or conical gears ( not sure of exact setup ) in the later bravo units instead of the old type dog gears. This made the transition between neutral/forward/reverse much smoother

 

[spannerman]

All Bravo drives have a clutch, the best drive for a 24ft sportscruiser would be the Bravo 1, the B2 is for heavy semi displacement and the B3 as Mapism said is for diesel or very high hp boats.
A B1 is the drive for speed, they don't give many problems as long as you stay on top of the surviving and have the drive off once each season to check the bellows for water ingress, I have changed lots of U/J's on Bravo drives due to poor maintenance, but internally they are rock solid and don't suffer from prop shaft seal failure like Volvo drive. In fact in 20 yrs I have never replaced a prop shaft seal, but I have replaced at least 20 every year on Volvo drives. I have a 5.7 260hp on an Alpha drive and it is 19 yrs old but as good as new.

 

[capnjack]

Hi Dom
James spotted Miss Molly up for sale and we were all wondering what was going on?

I think they've got a Bravo on their Regal 2250, might be worth asking them how they get on with it.

http://www.boatbanter.co.uk/viewtopic.php?f=15&t=570&p=4570#p4570

 

[julians]

I had a 2006 sea ray 200 select with a 5.0 mercruiser v8 (260hp) hooked up to an alpha drive. I owned it from brand new and it was maintained meticulously but after about 300 hours/4 years, one of the gears in the drive sheared some teeth off , which necessitated a rebuild.

We dont know what caused it, could have just been a freak failure, could have been a manufacturing fault, who knows, I know these drives are supposed to be fine when paired with that engine, but there was speculation that the relatively high HP of the engine coupled with lots of full throttle starts ( I did a lot of wakeboarding behind that boat) caused the drive to fail prematurely.

I should add that I've had other boats with the alpha drive (but lower Hp engines) with no trouble at all, but I think if you have free choice you may as well go for the bravo drive because of the more robust nature, and the fact they use clutches as opposed to dog gears which will mean smoother changes into and out of gear.

 

[mlines]

Yep - Bravo III with Duo-props on a 350Mag V8 engine.

I believe the repair costs would be high if it went wrong, but it is a world apart from the Alpha. The clutch makes it so smooth and a delight in close quarter handling. As you are looking at V8 engine boats then it will handle the power nicely. Standard maintenance costs for the drive are the same as the Alpha as it just needs oil changing and a general lube inside. As said above, get the UJ checked, cleaned and greased every year. This happened to ours between proper services...

Apparently an incorrect (older style) bellows was used on a previous service which are known to leak around the seal. However a clean and re-grease is all they need to recover.