Bravo III exhaust tube disconnected

[jumpjets]

Hey guys. I haven't been around in a while. I just bought a new to me 2007 Rinker Captiva 262 with a Bravo III sterndrive. The exhaust has a smooth tube instead of a bellow like my previous boats. The tube is firmly fastened to the boat, but there is a gap between the tube and the sterndrive. Is this OK? Is it supposed to be like that?

 

[alldodge]

This is correct, the B3 restricts exhaust flow because of the twin props, so the exhaust tube is used. The tube can be used with any Bravo or Alpha drive and only thing that may be noticed is a bit louder exhaust

 

[Bt Doctur]

perfectly normal when using a boot instead of a bellow

 

[dubs283]

Interesting to note is one of the original reasons for the use of the tube (pictured) instead of a bellows is on small block setups with bravo 3's the twin props created so much vacuum underway they actually collapsed the exhaust bellows and caused run ability issues due the engine not being able to exit exhaust gases with enough force to re-expand the bellows.

The solution was to use the tube, which now has become popular to install instead of exhaust bellows due to the ease of installation. It is a little more difficult to install the bellows especially without the expander tool. If memeory serves the tube is actually listed on some or mercury's online fiche for alpha's as replacement items for the bellows

 

[Bondo]

The solution was to use the tube, which now has become popular to install instead of exhaust bellows due to the ease of installation.

Ayuh,..... I haven't installed a bellows, since I first discovered the tubes,.....

 

[alldodge]

3's the twin props created so much vacuum underway they actually collapsed the exhaust bellows and caused run ability issues due the engine not being able to exit exhaust gases with enough force to re-expand the bellows

A B3 on a SB could collapse a corrugated bellows? I would think with that much vacuum the gear lube in the drive would be sucked right out with it. Have any Tech bulletins of other?

In BB apps it was because there wasn't enough room for all the exhaust so back pressure existed at high rpm range.

 

[dubs283]

Have any Tech bulletins of other?

Never read any bulletins on it, was just mentioned once in class. Funny you ask about the gear lube loss. There IS a bulletin on the propshaft seals on bravo 3's loosing gear lube while underway. They will pass a static and rolling pressure test but will loose lube when under a load.

Figured that one out before mercruiser while t-shooting the issue in the shop. Ran the boat in gear for three hours before noting the slick spot on the floor.

Scuttlebutt between mechanics brought up the vacuum issue and we thought, "Hey! if the vacuum can collapse the bellows could it also pull lube out a failing seal?" Maybe...

 

[alldodge]

I have a B3 on my cruiser and it will loose a tad of lube every so many hours, but never any water in the drive at end of season, just nature of the beast.

 

[jumpjets]

Hey guys, thanks for the info. Just so I'm 100% clear that this is a non-issue: Even when the drive is in the full down position, the exhaust tube still doesn't fully seat onto the sterndrive exhaust. There is a gap 100% of the time. This is OK as well?

 

[Bondo]

Ayuh,.... That's correct,....

 

[tpenfield]

It's all good. I went from bellows to tubes, since the bellows never seemed to stay on anyways.

 

[jumpjets]

Great, Thanks guys!! Time to hit the river.....