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2000 Mercruiser 4.3 Exhaust Bellows

GlastronGary

GlastronGary

Member
Installed a new exhaust bellows earlier this spring (what a nightmare) Problem is that it keeps disconnecting from the drive side when the tilt is all the way up for trailering. I have run it without being connected and it doesn't seem to bother anything, I've also heard about an exhaust tube that doesn't directly connect to the drive side. can anyone tell me more about this and is it important that the bellows be connected at both ends all the time.

Thanks in advance.
 
I'm fighting the same thing after replacing six on various boats. But I'm going to try again with a new bellows and adhesive. Why? Because Merc. designed it this way. The thru prop exhaust floods the prop shaft hsg, and helps cool the hsg. The flapper valves in the manifold risers help keep fast throttle shut down back waves from backing up into the exhaust manifold, but the bellows keeps this to a minimum. ...I'd like to see Merc. and Sierra add 1" length to the bellows. Trailer up is a tight stretch.
 
Suggestion: If your trim gage is working, raise the OD only far enough to clear the ground safely. You could make a mark on the gage where to stop it.

Jeff
 
The up cylinder travel limits the max. trailer up position. My previous boot jobs have held in this position.

I just re-read the manual an think I've found my problem. After applying the bellows adhesive to the hub tubes and bellows, you're supposed to wait 10 min. until it gets tacky. These last times I've been applying gobs and quickly pushing/pulling the bellows on thinking I could get it seated easier. Bellows adhesive is essentially contact cement, and apparently my thick wet coat hasn't cured and set up tightly. The other trick is making sure the bellows is pushed/pulled completely on the hubs until the end of the hubs contact the first convolution. Then insure the hose clamps are right up against the bead on the bellows clamp surface. Merc. didn't do us any favors with the forward bellows clamp. Everything has to be perfect to get a screwdriver thru those access holes and get it tight enough. I'm starting over with a new bellows tomorrow. I'll see if following my own advice here fixes this for good.
 
Thanks for the responses and tips on installation, just in case someone else is having troubles installing the bellows. I found a "YOUTUBE" video where someone used tie-wraps around the ribbed part and then more tie-wraps as pull handles for the tie-wraps around the bellows to pull the bellows onto the hub end and he was able to use a rope and tie it to the tie-wraps over the drive end and hold the bellows in place on the hub so he was able to tighten the hose clamp, it seemed to work pretty good when I used the same method.

https://www.youtube.com/watch?v=jJVfDbhwkwU
 
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I used my own advice and got mine to stick. I was out of bellows adhesive, and no one around had any Merc. or Sierra. Forums and one shop said they use 3M Weatherstrip Adhesive - black. Contact cement. I used this and I didn't overkill the dosage. Some say I might regret it if/when I have to remove the bellows. Another problem for another day.
 
and is it important that the bellows be connected at both ends all the time.
Click to expand...

Nope,..... Not really,..... You can use the exhaust tube insteada the bellows,....

It clamps to the transom, 'n sorta gloves into the drive when trimmed down,....
Just abit raspier tone trimmed up,....
 
bondo said:
Nope,..... Not really,..... You can use the exhaust tube insteada the bellows,....

It clamps to the transom, 'n sorta gloves into the drive when trimmed down,....
Just abit raspier tone trimmed up,....
Click to expand...
I was ready to go for this after mine slid off the third time. But I recalled that most thru the hull exhaust outlets have extra flappers to help the interior exhaust flappers keep fast throttle-off backwash from flooding those hot exhaust valves. So I kept with the Merc. design intent and made sure mine was hooked up solid on both ends. I cheat here and there in other places, but not in this case.
 
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