Exhaust manifold for Yanmar 3JH2E

[davjonLegend]

My mixing elbow cracked on my 1993 Legend 37.5.
Evidently Hunter Marine did not use the standard exhaust system for this engine.
Instead they created a custom 90 degree pipe between the engine and a mixing elbow from another Yanmar engine.

I need another 90 degree pipe (and its custom base plate). Hunter Marine wrote to me "Sorry but that company is out of business."

Does anyone know where I can find matching parts (90 degree pipe and base plate) for the exhaust manifold?

 

[Mike H.]

I have the same engine on my boat. I just boiled out the elbow in acid as it had corroded shut. There was a 1/2" plate steel adapter that bolted to the manifold, then a 1 1/2" bronze street elbow threaded onto it. A 1 1/2" bronze close nipple connected the street ell to the exhaust mixing elbow. Then the rubber exhaust hose was clamped to the mixing elbow.

I don't know what part is broken on your boat, but the street ell and close nipple are standard plumbing parts obtainable at any commercial plumbing supply. The adapter plate can be manufactured by any metal shop fairly inexpensively. $ 100. ?

Hope this helps,

Mike

 

[Don12364]

Me Too

I am in the same trouble with my 1996 model 3JH2E Yanmar except that my standard plumbing parts are black iron rather than brass and are shedding thick layers of rust everywhere - and it now leaks water too.
A few days ago, in our local Yanmar agents, I handled a beautiful bronze or brass cast version as now produced by Yanmar with their own part number. It looks to be a direct replacement for the Hunter original with the 4 bolt flange and within the Hunter overall dimensions - so it should go straight on.
The water is injected into a gallery which completely surrounds the exhaust pipe and thus cools both the mixing elbow and the rubber exhaust hose. No silly little (asbestos?) insulating collar needed either.
This item can be seen on the various diagrams in the workshop manuals.

Only snag is they sell at £300 = $480 US.
I'm tempted because it looks like a permanent answer to the clogging problem as well - and the brass water injection fitting simply screws in so is easy to clean. And the whole thing would be cleanable through the various holes in the casting.

Anyone tried one?

 

[davjonLegend]

Mike's suggestion to use a bronze "street ell" sounds like it would work. I thought my 90-degree part is cast iron. Not being an expert on materials, I figured that a bronze part on a hot exhaust may not survive the heat (over time). If it works, that sounds like a good solution.

Donalex -- Can you provide the Yanmar part number that you saw? It might be worth checking into also. Thanks.

 

[sj01]

I'm also wanting to replace mine. This looks like the one. http://www.manifoldwarehouse.com/mes/mgr?brch=mani&id=35

Saw it somewhere else for about $85, just have to find it again.

 

[dfast7181]

Look under the mid-sized boats posts under "mixing elbow" I posted the name of the engine shop that Hunter gave me. Now this was for a 2005 H-33 but the part you discribe sounds just like the exhaust manifold on my 33 (Yanmar 3YM30). It's a four bolt flange then 90 degree turn, coupler, then mixing elbow.
Hope this helps. At least it's a place to start.

Don

 

[Don12364]

Elbow listed by is not the new type I saw.

The mixing elbow picture posted by sj01 looks to be a version of the original and is not the one I handled.
The one I saw is shown in section 4 of the 3JH2E manual I downloaded in 2009 shown in the pictures below. (See the attached .pdf files for better detail.)

 

[davjonLegend]

Re: Elbow listed by is not the new type I saw.

I have finished my repairs and am reporting back.
The mixing elbow at the link by SJ01 looks identical to my new part.
For everyone's benefit, here's the Yanmar part numbers I used:
Mixing elbow = 124070-13520
Joint (threaded coupler) = 104214-13580
Gasket (for manifold) = 129472-18090

I re-used the 4-hole mounting flange, and the 90-degree pipe that connects the flange to the mixing elbow.
However, the 90-degree elbow can be found at a lot of places, such as plumbing suppliers or your local marine supply store -- it is called a "bronze stree-ell" -- which means it has male threads on one end and female on the other end.

Advice -- on the boat initially, the hardest part was separating the exhaust hose and the mixing elbow -- seemed to be bonded together. Lots of WD40 and soapy water, plus shoving a screwdirver down the hose, finally separated the two.
Separating the joint (threaded coupler) from the 90-degree pipe to the engine was really hard. Removed the exhaust manifold (4 bolts that came off easy) from the engine, went to a machine shope (or engine repair shop), and they heated the crap out of the parts (to cherry red color), used a 3-foot long pipe wrench, and finally broke the parts loose. Re-assembly of new parts in my garage, and re-mounting with the 4 bolts was easy. Be sure to use Never-Seize (or equiv) on all threaded parts -- makes life easier for the next guy.
Good luck to all.

 

[davjonLegend]

Re: Elbow listed by is not the new type I saw.

Minor spelling correction (missed the "t") -- "bronze stree-ell" should be bronze street ell.