Bellows Adhesive application

DJK555

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Sep 19, 2017
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I'm replacing the exhaust flapper on a 3.0L Mercruiser. The manual calls for the use of bellows adhesive on the rubber boots that connect the upper and lower exhaust tube, and I assume, on the boot that connects to the riser. Is the adhesive required in this application and if so what is its purpose other than to hold the parts on assembly. It would appear that two hose clamps per connection would create a good seal.
 

muc

"Retired" Association of Marine Technicians...
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Jul 7, 2004
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I'm replacing the exhaust flapper on a 3.0L Mercruiser. The manual calls for the use of bellows adhesive on the rubber boots that connect the upper and lower exhaust tube, and I assume, on the boot that connects to the riser. Is the adhesive required in this application and if so what is its purpose other than to hold the parts on assembly. It would appear that two hose clamps per connection would create a good seal.
Interesting, I don’t think I’ve ever seen adhesive recommend for MerCruiser exhaust tubes. What manual did you read that in?
 

DJK555

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Sep 19, 2017
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Mercruiser Service Manual Number 13 - Marine Engines GM 4 cylinder
 

Bondo

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Apr 17, 2002
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70,953
Ayuh,...... I've never ever used any sorta sealant on those points,......

If I did, I'd reach for Perfect Seal, over bellows adhesive,....
 

Baylinerchuck

Commander
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Jul 29, 2016
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2,726
Bellows adhesive even on bellows is a real pain in the butt and makes a mess. I’m with everyone else here and only use the clamps on the tubes.

Some of the other Rubber connections, especially coolant lines where the barbed ridge has rusted away, I’ll use Permetex Ultra Black as a sealant. It works well and can be peeled right off every year during annual service.
 

Kubaat3lover

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Jun 6, 2019
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How about bellow adhesive on Ujoint bellows? Is it the only place to use adhesive?
 

Baylinerchuck

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Jul 29, 2016
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How about bellow adhesive on Ujoint bellows? Is it the only place to use adhesive?

I had a lot of problems with the quick silver bellows adhesive. It’s more like a contact adhesive, similar to weather strip glue. Putting on a thin coat, letting it tack up, then installing the bellow on the horn proved to be very difficult because as soon as the two tacky surfaces meet, they instantly bond. A couple times the instant bond made the glue peel off the horn. Getting the cured glue off the rubber to make another attempt just downright sucks. I have a gen 1 outdrive, so mine has worm gear clamps on both bellow connections.

After a couple years of fighting the bellows adhesive, a member on iBoats suggested Permetex Ultra Black gasket maker. The only difference in application is to not tighten the clamp overly tight at first. Let the one side, (transom side), of the bellows set up for an hour or two, then fully tighten the clamp. Since I have a gen 1, I have to make the opposite side connection with a worm gear clamp on the bell housing side. The RTV makes things so much easier because I can line up the bellow on the horn and the RTV allows the bellow to slide on when I lower the drive fully. I’ll let it cure fully slid onto the horn. I’ll give it 4-5 hours, then raise the drive, and install and tighten the worm gear clamp.

Obviously if you have a gen 2 drive, you make the bell housing connection by pressing in the compression ring. I would still use Ultra Black here as well. I’ve never had or heard of one leaking since I used RTV. I wish I could remember who told me about this so I could give proper accolades.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,653
I use Evinrude gasket sealer ... it works well not too slippery and never hardens up. The Cobra has a groove in the gimble housing flange and a ridge on the bellows flange you have to line up....does the Alpha?
 
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