Exhaust Bellows

[chbrewer]

I have a Mercury 4.3 alpha and the exhaust bellows has come loose from the stern drive unit. My guess is it has been that way for some time and gone unnoticed. I am trying to determine if its ok to run the boat like this until I get fixed or if it needs to be fixed before using it again. I don't think boat is in danger of taking on water through the exhaust bellows, but is the engine or outdrive in any danger by running it? My guess is not since I have seen after market exhaust bellows that are open on the end facing the stern drive and don't even attach.

 

[sculbert]

Re: Exhaust Bellows

You should be fine. Just realize that your water and exhaust are expelled through there. think about carbon monoxides. And chance of filling your boat with water as well. If your bilge pump was to quit working. It isn't that hard to connect the bellows back up, I really don't see why you wouldn't go ahead and do that.

 

[chbrewer]

Re: Exhaust Bellows

From what I have read you have to take the outdrive off and pull the bellows hose on from the inside. So that seems like quite a bit of work.<br /><br />How would water get in the boat from the bellows? Is there not a valve in the exhaust somewhere to prevent water from flowing in from outside?

 

[JasonB]

Re: Exhaust Bellows

I was told last week by a very good merc mechanic that the exhaust bellows is non critical. The story was that the original exhaust bellows didn't clamp to the outdrive itself, they gust slipped over the horn. In later years, some people cut holes in them or removed them to help keep the plugs from carboning up as quickly and supposedly Mercruiser is going back to the original unclamped design. Don't know for absolute certain myself, but I trust the guy.<br /><br />Not sure about water getting into the boat from a bad/no exhaust bellows, unless the extra klength of the exhaust with it connected gives slightly less likleyhood of water reversition, but if the shutters are good......

 

[chbrewer]

Re: Exhaust Bellows

A local service guy told me the only harm was carbon buildup on the back of the boat from the exhaust and he said it could cause excess heat on the U joint? I don't know that I understand how it would cause excess heat though unless the hose got caught point toewards the u joint bellows area and heated it up.

 

[flashback]

Re: Exhaust Bellows

my old boat has just a tube on it. it does not connect to the drive at all (1979 Chris 350 merc), that was stock back then....

 

[hoot]

Re: Exhaust Bellows

the concern that i have if the bellows is remvoed was that the heat from the outlet under the drive bellows might shorten the life of that bellows. idleing or slow running would allow more heat to get to the drive bellows. at speed i wouldn't have a concern. some posters have said that their boat is somewhat louder with an exhaust tube. i think the tube is more expensive than a bellows.

 

[chbrewer]

Re: Exhaust Bellows

does anyone know any trick to reattach the outdrive end of the hose without having to take the outdrive apart?

 

[flashback]

Re: Exhaust Bellows

Actually Hoot, The entire drive, exhaust bellows, drive bellows, are under water at slow speeds so heat is not a concern, the exhaust is a little louder but not too bad........

 

[sculbert]

Re: Exhaust Bellows

Well I quess I was wrong on what we are speaking about here. I was thinking of the exhaust boot connecting the riser to the exhaust connector inside the boat. <br /><br />sorry guys.