I need to replace parts of my exhaust system. Mack Boring sent me a good diagram and parts list. In addition to the mixing elbow and the plate that connects to the exhaust manifold, the elbow assembly I need to replace includes a 1-1/2 inch 90 degree street elbow and a male-to-male 1-1/2 inch connector. They look like regular, everyday galvanized plumbing pieces I can pick up at Home Depot or my local plumbing supply house. Is there anything special about them (e.g., different thread size) that justifies paying the rather high price MB wants ($30 for one from MB vs. less than $5 at my local Depot)? Also, should I use every day pipe dope, anti-seize or something else to keep these parts from welding together the way the original parts have? As always, thanks for the advise. Tom
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Bill O'Donovan
They're different
So different as to be unique. Check with your yard for the two pieces. You have to dismantle at the manifold in order to get the mixing elbow off. Then you dismantle the manifold from the elbow and if you're lucky you can retain the reverse-thread flange that connects the two. The trick is to reassemble the new pieces as to to be snug and yet still go back on the engine gracefully. Don't even consider cleaning out an old mixing elbow, simply toss it for a new one. Well worth it.
So different as to be unique. Check with your yard for the two pieces. You have to dismantle at the manifold in order to get the mixing elbow off. Then you dismantle the manifold from the elbow and if you're lucky you can retain the reverse-thread flange that connects the two. The trick is to reassemble the new pieces as to to be snug and yet still go back on the engine gracefully. Don't even consider cleaning out an old mixing elbow, simply toss it for a new one. Well worth it.
I guess you could...
We have a 31' Hunter with a Yanmar 2GM20F. We bought the boat in 1999, replaced mixing elbow in 2000, then again in 2003. On the last time around, I just bit the bullet and ordered all three parts from Torenson without even checking to see if the sleeve or piece mounted to the block was service-able for another few years. How would you add the raw water intake/exhaust valve? Are you willing to take a chance on the structural integrety: those parts, if ruptured, will leak CO into the cabin. I believe you would be penny-wise and pound foolish. But I am willing to listen to what other, more experienced folks have to say. Joe on Alure
We have a 31' Hunter with a Yanmar 2GM20F. We bought the boat in 1999, replaced mixing elbow in 2000, then again in 2003. On the last time around, I just bit the bullet and ordered all three parts from Torenson without even checking to see if the sleeve or piece mounted to the block was service-able for another few years. How would you add the raw water intake/exhaust valve? Are you willing to take a chance on the structural integrety: those parts, if ruptured, will leak CO into the cabin. I believe you would be penny-wise and pound foolish. But I am willing to listen to what other, more experienced folks have to say. Joe on Alure
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Pat McCartin
I'll throw in $.02
Galvanived pipe fittings will work just fine. Consider a suport strap of some kind, if you are going to modify the design. The exhaust manifold has a limit to the stress & vibration it can handle. I repowered a Newport 30, 2years ago. Had to redesign the exhaust to fit around the cockpit sole/bridge deck. It's still going just fine. Consider that when Yanmar designed these parts they knew it would be exposed to salt water, therefore expendable. Pat
Galvanived pipe fittings will work just fine. Consider a suport strap of some kind, if you are going to modify the design. The exhaust manifold has a limit to the stress & vibration it can handle. I repowered a Newport 30, 2years ago. Had to redesign the exhaust to fit around the cockpit sole/bridge deck. It's still going just fine. Consider that when Yanmar designed these parts they knew it would be exposed to salt water, therefore expendable. Pat
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warren
exhaust
mine has gone every 6 years.new yanmar part cost about $110. part #124070-13500 for my 30QM
mine has gone every 6 years.new yanmar part cost about $110. part #124070-13500 for my 30QM
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Tom FitzGibbon
Oops, let me clarify
I'm not suggesting replacing the mixing elbow itself with anything other than a Yanmar elbow. On my engine, a 90 degree street elbow connects directly to the exhaust manifold. A male-to-male connector threads into that. The mixing elbow then connects to the other end of the male-to-male connector. It's the 2 parts between the manifold and the Yanmar exhaust elbow I am wondering if I can get at Home Depot.
I'm not suggesting replacing the mixing elbow itself with anything other than a Yanmar elbow. On my engine, a 90 degree street elbow connects directly to the exhaust manifold. A male-to-male connector threads into that. The mixing elbow then connects to the other end of the male-to-male connector. It's the 2 parts between the manifold and the Yanmar exhaust elbow I am wondering if I can get at Home Depot.
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Royce
I used galvanized
When I had a yse12 in my boat I used galvanized nipples and 90's. I also made a water injection piece out of SS pipe piece and a 1/2" nipple welded in at an angle. I insulated the assemble to keep the heat down. I had this arangement for the last 7 years till I repowered the boat. I used a high nickle anti-sieze compound for thread sealant on the nipples. My water injection piece lasted much longer than the cast iron one I purchased from Yanmar. Hope this helps Royce
When I had a yse12 in my boat I used galvanized nipples and 90's. I also made a water injection piece out of SS pipe piece and a 1/2" nipple welded in at an angle. I insulated the assemble to keep the heat down. I had this arangement for the last 7 years till I repowered the boat. I used a high nickle anti-sieze compound for thread sealant on the nipples. My water injection piece lasted much longer than the cast iron one I purchased from Yanmar. Hope this helps Royce
Connector is right/left thread.
Tom: When you take the manifold apart from the elbow, you will discover that the connector has a left hand and a right hand thread. I doubt that you are going to find this part off the shelf. These part are VERY difficult to get apart, but not impossible. I suggest that you have a large vise, large pipe wrench and a breaker bar for the pipe wrench. You will also want to have a torch to heat the elbow and the manifold to assist in the dis-assembly. When you reassemble the parts be sure that you apply a liberal about of Never-Sieze on the threads.
Tom: When you take the manifold apart from the elbow, you will discover that the connector has a left hand and a right hand thread. I doubt that you are going to find this part off the shelf. These part are VERY difficult to get apart, but not impossible. I suggest that you have a large vise, large pipe wrench and a breaker bar for the pipe wrench. You will also want to have a torch to heat the elbow and the manifold to assist in the dis-assembly. When you reassemble the parts be sure that you apply a liberal about of Never-Sieze on the threads.
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