Exhaust Y-Pipe - Fix or Repair?

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Glaspar_Fan

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I have a Searay with an Alpha outdrive (~1986) and a Chevy 350. The exhaust Y-pipe (3", non-symetrical bolt pattern) appears to be leaking judging from where I can see water trickling in while the engine runs on the trailer. When I had the outdrive off, I felt around with my fingers and looked with an inspection mirror and it seems there is some significant pitting corrosion on the Y-pipe at the bottom. From what I've read on the forums, these things are a common source of leaks. As near as I can tell with my fingers, the transom plate seems to be in good shape.

The real problem is that no one (Mercruiser or anyone else) seems to make them any longer. Am I missing something? Where does everyone else get theirs? Used ones on Ebay seem iffy and must be gold plated judging from the prices. Anyone out there ever try fixing one by taking it to a welder and having the pitting ground out and built back up? How well did that work? Or has anyone ever tried fabricating a replacement?

As a last resort there is some epoxy filler in the iBoats store that claims to be a permanent fix for pitting and leaks in the exhaust system. Anyone tried that? I know the other last resort is a block-off plate and through the transom exhaust, but I really don't want to go there. This is a family boat, not a racer and the noise would be an issue.

Thank you for your time,

John
 

Howard Sterndrive

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if you launch-ski/tube-then back on trailer. sure.

But to leave a boat floating by epoxy isn't something I would do. I know the whole boat is sort of epoxy, but rotten/pitted metal is an active thing that tends to get worse. To properly epoxy would require prep that couldn't be properly done in place.
 

Bt Doctur

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4 inch can replace the Y pipe. only use`s 3 bolts instead of 4
 

Scott Danforth

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depending on the corrosion, I would either replace with a craigslist or ebay find, or blast it and take to my local aluminum welding guy and have it welded up.
 

Volphin

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There's also a good chance you could find a marine junkyard and have one pulled for you.
 

Glaspar_Fan

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Thank you all for the good advice. I may try some epoxy as a very temporary patch until the y-pipe can be removed. When it's out of the boat, I'll see about getting some welding done on it as a permanent fix.

If the pipe is too damaged for economical repair, I would also like to look into both the 3" and 4" pipes (I have the 3"). Can anyone tell me what years or engines (with Alpha drives) the 4" pipe was used on?

I've done a bit of metal and glass fabrication before (built my own sports car) so I'm disappointed that no one has tried to fabricate a new y-pipe. Although it seems like a very doable exercise, I'm not sure I want to be the pioneer.

Thanks again for the help,

John
 

Bondo

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Thank you all for the good advice. I may try some epoxy as a very temporary patch until the y-pipe can be removed. When it's out of the boat, I'll see about getting some welding done on it as a permanent fix.

If the pipe is too damaged for economical repair, I would also like to look into both the 3" and 4" pipes (I have the 3"). Can anyone tell me what years or engines (with Alpha drives) the 4" pipe was used on?

I've done a bit of metal and glass fabrication before (built my own sports car) so I'm disappointed that no one has tried to fabricate a new y-pipe. Although it seems like a very doable exercise, I'm not sure I want to be the pioneer.

Thanks again for the help,

John

Ayuh,.... 2 reasons come to mind,... a Good replacement is reasonably Cheap,..... 'n if yer Wrong with yer design, the boat Sinks,........ I've got a corroded y-pipe hangin' over my weldin' bench, I bought a Better 1, rather than weldin' the old 1 up,....... It might become a piece of a sculpture someday, but it won't on a boat of mine as a y-pipe,... too much weldin', 'n grindin' to get it Right,...
 
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90stingray

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Just need to pull the engine, remove the y-pipe, and cap off exhaust passage. Reinstall engine, then cut holes for thru hull exhaust and enjoy!
 

Cptkid570

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Have you tried anything yet? I had a leaking y-pipe and the best way to tell exactly where it was leaking was when it was sitting in the water, engine off, everything around me quiet, and then I got down there as far as I could with a flashlight and mirror. I don't know if I would've noticed the leak while running on muffs in the driveway. Have you confirmed that it is the Y-pipe? You'll need to know exactly where to put the epoxy.

A problem with welding a y-pipe is that if it is so corroded that it is leaking while it is installed, it will break apart even more while you remove it..

Another option.... To change your y-pipe, you have to pull the engine anyway. You could change out the transom assembly (gimbal housing) to a newer one with the 4-bolt pattern. Then you would have a y-pipe that isn't obsolete. I don't know the answer to this, but is the 4 bolt y-pipe only on Generation II alpha or did it come along on Gen one also? you'd want to make sure that there is a generation 1 gimbal housing that is 4 bolt that fits your outdrive. But, if it does, then you can probably find a used gimbal housing for not too much $$ on craigslist.
 

HT32BSX115

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Ayuh,.... 2 reasons come to mind,... a Good replacement is reasonably Cheap,..... 'n if yer Wrong with yer design, the boat Sinks,........ I've got a corroded y-pipe hangin' over my weldin' bench, I bought a Better 1, rather than weldin' the old 1 up,....... It might become a piece of a sculpture someday, but it won't on a boat of mine as a y-pipe,... too much weldin', 'n grindin' to get it Right,...
Yeah. welding corroded aluminum is VERY difficult. The Y-pipes are made of a weldable alloy but it's fairly thin made thinner in places by corrosion and you must grind all the corrosion away before attempting it.

It's not worth the trouble IMHO.

I found several on EBAY for about the same cost of a weekends worth of marina gasoline. I think I'd be buying a good used (fresh water) Y-pipe instead of trying to epoxy the one you have.

The work involved to get the thing off and back on makes it worth it.

You DO know you MUST remove the drive AND remove the engine (in that order) to R&R the Y-pipe?

THEN, you install the "new" Y-pipe, align the engine and THEN reinstall the drive.

All that work would keep me from just slopping some epoxy on and calling it good.

(Because you would be doing it all over when it started leaking again...)

Just saying...............


Rick


(didn't someone once say: Why is there never time to it "Right".............. but there's always time to do it over again?........[or something like that.......]
 

Glaspar_Fan

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I haven't done anything yet, but am planning on getting a usable used part. I'd go with the block-off and transom exhaust if it weren't for the noise. And yes, I understand the process of disassembly/reassembly - I recently replace both the outdrive and engine. Sure wish I'd known about the leak then.

If/when I try the epoxy, it will only be a very temporary patch and administered from the backside without removing anything other than the rubber exhaust tube. With the outdrive up and the tube off I can get get an inspection mirror in and can see the pitting. Seems like from that cursory inspection that the transom assembly is in good shape, just the y-pipe is pitted.

I've done all the inspection I can in the water and out. It's only possible to see a little bit from the inside even with mirrors, but I can see water trickling down below where the y-pipe is bolted to the gimbal. That trickle is about the same with the boat out of the water and the engine running as when the boat is in the water and the engine is off. It might be a bit more in the later case actually. I did check around the water inlet tube/hose but all the connections appear dry.

Thanks again,

John
 

Cptkid570

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Well, I do like the thought of at least trying the epoxy since it will be relatively easy to get to (removal of the exhaust tube). And, once you are done with that, then you can see if the trickle is gone. If it is gone, then you know for sure what the problem is and it could be a winter project with hopes that the epoxy holds through the summer, or at least slows down the leak. Just make sure you have a good bilge pump just in case.

Question out of my own curiosity...what epoxy would you use? Would JB Weld work better?
 

Glaspar_Fan

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I was originally figuring on JB weld since I have some already. It's great stuff, but it can run and sag while it's in its workable state. I'll do a little research before making the choice. If anyone has suggestions of epoxy pastes it would be great to hear them.
 

Bondo

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I was originally figuring on JB weld since I have some already. It's great stuff, but it can run and sag while it's in its workable state. I'll do a little research before making the choice. If anyone has suggestions of epoxy pastes it would be great to hear them.

Ayuh,.... You can mix yer own with resin, hardener, cabosil, micro-spheres, ground glass, 'n/ or chopped glass,...

I'd be concerned with gettin' it apart this winter, 'n gettin' rid of the epoxy ya wanta slather on it,....
 
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Bondo

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I've seen this done but would hesitate to do the same on my own boat. Am I wrong?

Ayuh,.... Donno,.... When presented with that question once, I sprang for the Right pipe,....
 

Vincentgould

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I have done this to my 1992 sea ray. It worked after 5 fails. It is so hard to get in there to clean it up properly. I just kept pealing it off and reapplied it until it stuck. Also, make your patch go over a very large area, that way you have more adhesion.
 
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