Melted hull through exhaust leaking water, replacement parts suggestions?

Hey guys first post here on the forums, to make a long story short I noticed boat was leaking extremely bad it’s a 2005 moomba Mobius LSV, found the problem was the plastic hull through exhaust was leaking. Took off the 90 degree elbow underneath noticed it was soft and warped and the plastic piece it clamps to was warped and melted. (Pictures included). Is there anywhere to order the oem parts online rather than going through a dealer? They said over a month to get the parts and they are over 4 hrs away from me. And that means my season is over. Could I go with some aftermarket parts? Pics included. Anyone that can shed some light on this would be greatly appreciated. Thanks! Also why do you think this happened? Is it a common problem or did the boat overheat causing the water in the exhaust to melt everything?

If you;re working on an older(er) inboard boat, you need to know the folks at Discount inboard Marine (skidim.com).

Looks like some of these products are close:
https://www.skidim.com/Mufflers_Sile...ducts/1025/2/0

If you don't find what you need, call them. Their tech team is about as good as they get.


Also, if you have part numbers, check Great lakes Skipper (greatlakesskipper.com). They've got TONS of parts but a little less tech support than skidim.

Thanks for the reply. I did check their website they have an exhaust flange in 3” but I measured mine at 3 1/4 “ unfortunately. It’s the same exact looking part though. I found another exhaust flange on activewake.com for a moomba the exact part but says it measures at 3 1/2 inches. Is the measurement outside diameter or inside diameter? The exhaust elbow is 3 1/4 exact inside diameter as well. Does anyone know what the exact size of the elbow and flange are? I am only able to fine 3” or 3 1/2”. I’m thinking it could be the 3 1/2 inch measuring outside diameter.

The 3.5 is the outside diameter. I'm pretty sure I got a pair from skidim for my 92 supra and they were the exact same part for my 2008 Moomba XLV.

Yes, I'm pretty confident that your boat overheated once and that it warped the plastic. On mine, I ran one year and didn't tighten the screws on my water pump and blew the cover off. The boat got hot and went into protection mode and I realized what was up. Not hot enough to damage the engine, but hot enough to melt the upper elbows that go into the top of the manifold. Then over a year later I found the parts leaking like yours. I almost sunk!

I got the new ones and put them on. I also ran a handful of stainless screws on the inner flange so that the exhaust elbow had something to bite into (I made it 'studded'). The flange has a taper and the inside diameter of the hose is bigger than the outside diameter of the flange. The best success is to get the elbow as close to the hull as possible, secure it so it's biting into the studs, and then attach the top end of the elbow trying to NOT pry the elbow off the flange in the process.

I had to fight with mine a few times before I finally got it on secure for good.

Call skidim on the phone and they'll verify that their flange is right for your boat, I'm sure it is. If water's running though your exhaust, it won't melt in the future.

Thanks for all the replies I got everything ordered and figured out. Had to order from a dealer through skiers choice. It ended up being 3.5. Still waiting on parts going to get it al back together and let you know how it goes. Thanks guys!

So I got all the personal from skiers choice turns out they don’t make the parts for the moomba anymore or the manufacturer who made them has quit. Instead they sent me parts that I have to “retro fit” aka ghetto rig. �� they didn’t tell me this until I received the parts and they cannot he returned. Here Is the old one exhaust vs what they sent me. The old exhaust is 3.5 inches OD. The new one is supposed to be 3.5 but is really 3.25 so it has a ton of slop in the hull. Thy said just “silicone it”. Also the flange is is so much larger it hits the trim plate on the back so I’m going to have to hack it up. Also I’ll have to trim it because it’s so long the part that goes into the hull. Is it okay to install this part with all the slop, I mean the screws will be holding it in, it is a pretty thick study piece of plastic compared to the old one that melted. Along with sealant it should be water tight it just doesn’t feel right. I’m at a loss guys. Not sure what to do. Any help would be appreciated

That sucks. I traced down the invoice where I bought mine from Skidim.com 5 years ago and found that they were labled as:

Flange, 3.5" exhaust
Item # 100699
$10ea

But I don't see them on the skidim website anymore. it might be worth calling them.



And I can tell you that even with the real 3.5" part, that it's going to be a bitch to get the hose to stay on. I almost sunk my boat! Not kidding. There's another Moomba member that had the same experience with trying to keep his hoses on his exhaust flanges. Now with the new ones, you could certainly get a piece of silicone tubing and sleeve it. Not what I'd be excited to do however.


My only other thought is that sometimes people have replaced their exhaust flanges with a newer style like what you received when they put the Fresh Air Exhaust (FAE) on their boats. Maybe someone has that style like we have that they pulled off their boat? Or maybe even contact the FAE company and ask if they by some miracle have one laying around that would fit your boat? OR, bite the bullet and use this as an opportunity to go with a FAE solution. I'm SURE that the FAE guy will have something that's a better solution than what that dealer sent you. Honestly it's worth at least talking to him because I bet no one will know exhaust flanges better than FAE!

Quote:

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Originally Posted by trayson

That sucks. I traced down the invoice where I bought mine from Skidim.com 5 years ago and found that they were labled as:

Flange, 3.5" exhaust
Item # 100699
$10ea

But I don't see them on the skidim website anymore. it might be worth calling them.



And I can tell you that even with the real 3.5" part, that it's going to be a bitch to get the hose to stay on. I almost sunk my boat! Not kidding. There's another Moomba member that had the same experience with trying to keep his hoses on his exhaust flanges. Now with the new ones, you could certainly get a piece of silicone tubing and sleeve it. Not what I'd be excited to do however.


My only other thought is that sometimes people have replaced their exhaust flanges with a newer style like what you received when they put the Fresh Air Exhaust (FAE) on their boats. Maybe someone has that style like we have that they pulled off their boat? Or maybe even contact the FAE company and ask if they by some miracle have one laying around that would fit your boat? OR, bite the bullet and use this as an opportunity to go with a FAE solution. I'm SURE that the FAE guy will have something that's a better solution than what that dealer sent you. Honestly it's worth at least talking to him because I bet no one will know exhaust flanges better than FAE!

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I just order these last year, I'm pretty sure from Skidm, did you call them?

Yeah I called them they don’t have anymore. They were getting theirs from skiers choice. The manufacturer who makes them for skiers choice quit making them. So anyone who needs the exhaust flange is either going to have to get the Supra ones which don’t quite fit or stainless aftermarket options. THanks for all your help guys I ended up installing the supra parts I got from skiers choice.

Had to replace my flanges and hoses 3 years ago on 2014 MOJO. Got them from Atlanta Marine from their stock. Shipped next day. Might check with them.

Quote:

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Originally Posted by Badfoot

Had to replace my flanges and hoses 3 years ago on 2014 MOJO. Got them from Atlanta Marine from their stock. Shipped next day. Might check with them.

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You know this thread is 7 years old? [emoji1787][emoji1787][emoji1787]

Sent from my motorola edge plus 2023 using Tapatalk

7 years, it's like bourbon coming into age.

Quote:

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Originally Posted by trayson

You know this thread is 7 years old? [emoji1787][emoji1787][emoji1787]

Sent from my motorola edge plus 2023 using Tapatalk

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Just catching up. HA.
Well that's embarrassing. Not sure how I got on that thread. Please excuse my lack of awareness.
Sure hope he got it repaired.