SS U-Mixing Elbow

Oct 29, 2005
2,355
Hunter Marine 326 303 Singapore
About 2+years ago I fitted an SS U-MIXING Elbow bought from eBay. First year check, I reported the U elbow to be in great shape and no rust build up whatsoever.
Now pass 2nd year, I've checked the U elbow and glad to report that it's still as clear of any rust or fouling. Totally as good as new!!
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Now pass 2nd year, I've checked the U elbow and glad to report that it's still as clear of any rust or fouling. Totally as good as new!!
Thanks so much for the information, Ken. I was hoping you'd be posting further results on your original installation. I am going the SS route this summer as mine is getting to the end of its life expectancy with the separation wall corroding away.

Most interesting what you say about the interior gas passage being free of carbon fouling.

Dirty Sectioned Mixing Elbow.jpg

Don't know why the carbon doesn't stick when the hot gasses hit that cold surface but don't really care either, as long as it's doesn't.

Can you please post the supplier of your SS elbow as there seems to be a couple of them on e-Bay ? I don't think the market is floating in SS elbow forgeries but I would like to ensure I have the one you originally purchased.
 
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Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
How many engine hour do you think it lasted?
Seems to crap out in an unholy mass of carbon and rust every 5 - 6 years (5-600 hrs.). It's the corrosion I spend sleepless nights over. I did come up with a half-assed method of cleaning the carbon out of the elbow, but it's the corrosion and possible sea-water going back into a cylinder that keeps me replacing these things on a regular basis.

https://forums.sailboatowners.com/index.php?threads/torn-from-the-pages-of-ripleys-believe-it-or-not.182930/&highlight=mixing elbow
 
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Jun 21, 2007
2,105
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
I installed a SS exhaust elbow on my Yanmar 2QM20 two years ago. When "down" in the engine compartment just this past week I saw that the elbow from the outside looks identical to the day that I installed it. I haven't put many engine hours on the thing.

But neither did I with the previous Yanmar official replacement elbow, made of cast iron, that failed after only three years. Carbon build-up was not the issue. Instead, I believe that shape of the OEM part allowed the salt cooling water to pool in it and sit between outings. Then over time, caused etching and corrosion through the casting. In comparison, the SS elbow has a straight shot route out for the cooling water to drain completely. Also SS probably is more resistant than cast iron to rust breakdown.

Here is a cut-and-paste of a posting I made in July 2016 after installing the SS elbow: Note the picture of the failed Yanmar official part elbow.

=======================================================================


The first attached photo is of the second Yanmar cast iron OEM elbow that I had replaced on my 2QM20. The first one failed the same way. The second probably had only 200 hours on it... but 4-5 years and say ~150 outings. I discovered the crack after not using my boat for 6-7 months (wasn't a good idea to go sailing while recovering from a broken neck). I suspect that the cause of the failure might be that a puddle of raw (sea) water would remain in the elbow's "bulge" each time the engine was shut off.

This time I did replace with a stainless steel elbow. Rather than through the eBay portal, I bought it direct from www.exhaustelbows.com. (Update: I just clicked on this link and came up "not found" ).

I have also attached a photo of my SS steel elbow installation. It's only been about 5 months now since I purchased. So too early to determine how it will do over the long term. But this replacement has a straight run down to the exhaust hose. No bulge to allow the "puddle" raw water to remain between engine uses. The price seemed right and worth the experiment ... even though I also had seen some posts that SS might not do well for exhaust elbow duty. Looks very pretty though!

Attached Files:
 
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Dec 14, 2003
1,393
Hunter 34 Lake of Two Mountains, QC, Can
Got mine from same source as Ken last February. About 200 hours since. I guess I was vain enough to want it to look real good so I nought the polished version for $20 more LOL. Only change seen since is a little bluish color starting to appear on the mirror like finish because of the heat !
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
Ralph, I got mine from this link. It also comes in U-mixing elbow+joint (minus exhaust elbow which you can reuse the old ones).
Thanks so much, Ken.

I received a PM from @Charles Erwin saying that the company who machines these castings (investment casting is from China) is HDI Marine who is in our collective backyards in Vancouver, Washington. After sitting down to order one of these, I see that all SS Yanmar elbows on eBay are from hdimarine in Vancouver.
 

EAMc2

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Oct 1, 2016
11
Hunter 37C Cherubini Palm Beach, FL
We just replaced our mixing elbow on our 1979 Hunter 37C, which has a Yanmar 3JH2E, with a stainless steel mixing elbow from HDI Marine. They are super to work with and a family owned business. They had not ran any like ours before and stated they had another request for the same type, so they ran a small batch of our style. Great service!

hdimarine.net
971-255-9139
SS mixing elbow from HDI Marine.JPG
 

cptjak

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Apr 13, 2010
21
CS 36 T Channel Islands Harbor
Hey EAMc2 I have the same Yanmar is that a 2" exhaust hose
 
Jul 1, 1998
3,062
Hunter Legend 35 Poulsbo/Semiahmoo WA
Several years ago I was going to do like Ralph Johnstone did (post #2) and cut the old one in half. Didn't get to it right away, it got kicked around in the garage, then when I finally did get to it a few years later there was a surprise. When I picked it up there was a lot of crumbly stuff that came out - old carbon and who knows what else. At that point there was no need to cut it in half because all the blockage evidence was gone.

In the summer of 2016 I put on a SS elbow [had to get the coupling and the gasket separately] and so far, so good. Also put in new injectors and the engine runs really well but, unfortunately, there is very little discernible difference from the old injectors so now there is a set of spares.

If the seller would include the coupling and the gasket in a package that would be super. One stop shopping.
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
I replaced my elbow the previous off season with a SS one. I haven't looked at it since. My whole reason for doing it was one less system failure point to worry about. My shaft seal is now in work - same reason.
 

EAMc2

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Oct 1, 2016
11
Hunter 37C Cherubini Palm Beach, FL
cptjak,
I believe it is 2", I will need to check for sure. It fit perfectly into what we had. I will get back with you to confirm.


Ralph,
It is the water inlet pipe.
The additional hole is a threaded temperature gage hole, HDI supplied us with a threaded plug, as our original mixing elbow did not have a threaded temperature gage.
 
Jan 4, 2006
6,444
Hunter 310 West Vancouver, B.C.
It is the water inlet pipe.
Perfectly obvious .................. once it's pointed out. Ideal place for a hi temp. alarm whereas with the GM series elbow, that hole is used for the sea water inlet

I use a flow sensor to make sure sea water is flowing before we get the show on the road.
 

SFS

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Aug 18, 2015
2,066
Currently Boatless Okinawa
Well, I just called these folks (HDI Marine) in Vancover WA and ordered the whole kit for my 3YM20. It's a family operation (a father, son, and daughter), and I talked to the daughter (Haley). She answered all of my questions, and will ship the unit today, even though I caught her at 10 minutes before closing. If the product is as good as the customer service, I will be very pleased.

I needed a new upper elbow, as my casting apparently developed a pinhole leak and is looking bad. I took it off today, along with the lower elbow, and went to my local Yanmar dealer. The upper elbow would have been about $200, the lower about $145, for a total of $345, assuming I could reuse the riser between them. I paid LESS than that for a complete system, including a new 9" riser and a gasket for the engine side of the lower elbow, all in stainless.
 
Feb 21, 2008
408
Hunter 33 Metedeconk River
I think I might have to replace my mixing elbow. I watched the video on youtube. Is the project as easy as it appears?
 

Sailm8

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Feb 21, 2008
1,746
Hunter 29.5 Punta Gorda
I think I might have to replace my mixing elbow. I watched the video on youtube. Is the project as easy as it appears?
It can be but it all depends on how hard it is to get the elbow off the manifold. Take the manifold off the block and put it in a big solid vice. Grab the elbow with the biggest pipe wrench you can find. I had to resort to a torch to heat it up and separate. I reassembled with antisieze.
 
Feb 21, 2008
408
Hunter 33 Metedeconk River
Thanks Sailm8. I guess I don't have to do that if I am replacing all the pieces shown in
Ralph's #13 picture.