exhaust tube or bellow?

Ashmanmb

Cadet
Joined
Jun 28, 2012
Messages
8
What are the pros and cons of exhaust tube vs bellow.

My alpha 1 exhaust bellow (the new one I put on last year), is broken in the middle. I can only think I somehow damaged it when installing it causing a small tear to appear then it ripped open. I did it without removing the stern drive, and used some large vise grips to hold it in the stretched position to get it on - after messing about for a while, got it on and all was well. I think with the boat sitting it either tore because the motor ws all the way up stretching on it and the rubber was still new and tight, or maybe a rodent got into it. not entirely sure.

Anyway I was reading on exhaust tubes and noticed they only attach on one end. hows does this work. say I back the boat in with the motor up into the lake to make sure it clears then then lower it, does the tube allow water to get into the manifolds or is there something that will prevent it. how does it work when I am adjusting the trim when driving since the exhaust is pushing outwards does that prevent water from getting in the engine? what if I have to cut the throttle when I have a skier behind me, will water push up into it and get into the motor?

I am planning on ordering the parts but not sure what is the best to go with, new bellow or exhaust tube. Any thoughts?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: exhaust tube or bellow?

You can't replace exhaust bellow (or uni bellows for that matter) without removing the drive... PERIOD!!!!

The exhaust bellows doesn't stop water getting it. When you shut the engine off, the bellows floods... What stops water entering the manifolds is gravity.. Water can't climb up...

The tube was used for a few years only, and it was to relieve back pressure, which is now done with the relief holes in the side of the gimbal housing.

Most people with tubes don't like the noise, hence Merc went back to bellows..

Which one you use is your call... Like noise (but also think about the people around you)... use the tube, don't want the noise... use bellows.... Either way... TAKE THE DRIVE OFF to replace them....

Chris........
 

dan t.

Lieutenant Junior Grade
Joined
Feb 28, 2008
Messages
1,137
Re: exhaust tube or bellow?

Go for the tube, the increase in noise is barley noticeable, and yes you can install a tube without removing the drive.
 
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