Yanmar YSB 8 mixing elbow

[Halifax Sailor]

Went to the boat and elbow is cracked. CO monitor goes off so am losing exhaust when I run the motor. Can see what looks like a crack (soot on threads below and on close cooling hose), and elbow is at least 7 seasons old (I have had boat that long). Wondering if there is debate between OEM, replacement stnlss or similiar manufactured products. And as I am in Canada, has anyone sourced in Canada? Yanmar part is 104214-13521 for those who may have some info. I know Yanmar is usually bit more expensive but as this is vital equipment in my mind, would look at OEM original cast steel unless someone has other opinions............

[Compass790]

Originally Posted by Halifax Sailor

Went to the boat and elbow is cracked. CO monitor goes off so am losing exhaust when I run the motor. Can see what looks like a crack (soot on threads below and on close cooling hose), and elbow is at least 7 seasons old (I have had boat that long). Wondering if there is debate between OEM, replacement stnlss or similiar manufactured products. And as I am in Canada, has anyone sourced in Canada? Yanmar part is 104214-13521 for those who may have some info. I know Yanmar is usually bit more expensive but as this is vital equipment in my mind, would look at OEM original cast steel unless someone has other opinions............

Yes I certainly have an opinion!
I think the original cast-iron elbow is a fatally flawed design in that with its water jacket on the elbow that can leak into the pipe rising from the exhaust port. This has killed many a yanmar when salt water drops down into the exhaust port.Of course if you replace every 4 years as yanmar says you would be ok but too expensive for me.
I fabricated my own out of sched 10 316L ss pipe & put the water injection point on the downhill side of the elbow just above the point where the exhaust hose attaches. This ensures that the salt water can only go to the exhaust outlet rather than back in the engine ( unless you invert the boat)
Not sure how long my pipe will last but 15 years + will be a minimum .You can buy cast ss 316 exhaust elbows. Try HDI marine but they may have the same design fault tho they'll last longer than cast-iron
I tried to attach a photo. easy for a welder to make one the same. You can do it with stick welding easy.

[grantmc]

A photo would be helpful.
If just a crack then can be welded. If you'd prefer cold weld then there is a good epoxy from YB Weld that would do the job. If hot welding then I'd drill at hole at each end of the crack first (to allow for heat expansion).

[Halifax Sailor]

I will grab a photo when at the boat today. The crack runs from the bottom (exhaust side) to 3/4 to the top. Its on the flat side of the elbow. There is soot from the exhaust around the screwed in adaptor between the elbow and the exhaust manifold and also soot on the hose that inputs water into the elbow from the engine. So first glance without trying to take apart, looks like the split is big enough that it leaks around the threads. So this one may be toast with a crack running too far too weld. If I was away, would prob try almost anything but end of season, boat is home, weird season anyway, think I will replace with whatever I can find, opinions very welcome as this is first issue (major one) I have had with the engine. I know, very lucky but a YSB is a very old simple design. I take good care of it, change oil every 30 hours, 1 litre, big job!!! Starts every time without issue so think I will replace the offending part. By looks of it, it may just collapse when I put my wrench on it anyway.

[hpeer]

Try these folks for aftermarket options. I bought a Yanmar elbow from them. It was of FAR higer auality and lower proce than OEM.

https://hdimarine.net/

If uou dont see what hou want right away give them a call. I found them very responsive.

[const0022]

I had a similar problem, but after quite a few years on a cast iron exhaust elbow on my Bukh deisel. However, I was advised to paint the inside with several cost of epoxy paint. I taped up end with tape and rolled paint in every direction and threw away excess. I think I did three or four coats. Never had a problem again! Had the boat 27 years from new. Now recently faced with a stainless steel exhaust elbow leaking on my motor yacht which is now 10 years old. It's been welded now but engineer suggests replacing section in due course as it's worn thin by passage of hot salty water. 2800 hours on engine though.

[Russ]

My HT 110 hp Yanmar elbow failed in the Bahmas I learned that although Ynamar sells the engine elbow attachment often the rest is a custom fit. Also in the Bhamas NOTHING can be shipped OUT by air unless there is an accompanying passenger. Big PIA to get the original out and back in custom fabrication was easy as I had the part and the original engine installer was still around and they built the first one. Best shop around and be sure you have ALL the parts to make an elbow that will fit.

I would not trust a weld ONLY because if it fails and you are far away from CAN/USA you may be totally screwed.

PS I had an extra "elbow" from Yanmar on board and it fit but it was NOT the section that failed! The elbow in Yanmar terms is the elbow where it attaches to the engine and ends there the rest is custom.
Russ

[Compass790]

Originally Posted by Halifax Sailor

I will grab a photo when at the boat today. The crack runs from the bottom (exhaust side) to 3/4 to the top. Its on the flat side of the elbow. There is soot from the exhaust around the screwed in adaptor between the elbow and the exhaust manifold and also soot on the hose that inputs water into the elbow from the engine. So first glance without trying to take apart, looks like the split is big enough that it leaks around the threads. So this one may be toast with a crack running too far too weld. If I was away, would prob try almost anything but end of season, boat is home, weird season anyway, think I will replace with whatever I can find, opinions very welcome as this is first issue (major one) I have had with the engine. I know, very lucky but a YSB is a very old simple design. I take good care of it, change oil every 30 hours, 1 litre, big job!!! Starts every time without issue so think I will replace the offending part. By looks of it, it may just collapse when I put my wrench on it anyway.

i wouldnt try repairing it as you will end up chasing your tail as it will be corroded throughout at 7 years old.
Also as i said in earlier post you risk dropping salt water into the cylinder which ages your ysb8 rather quickly.

CORRECTION: just to set the record straight Yanmar doesn't say to replace mixing elbow every 4 years ( I checked the manual ) it says to inspect every 300 hrs.
I think a yanmar serviceman told me to replace it every 4 years.

forgot to say in earlier post that i wrapped the fabricated exhaust in ceramic wrap up to the injection point.

Yes the ysb8 is a simple long lasting design that is easily rebuildable with a wet sleeve. Other thing to keep an eye on is the oil pump tolerances as they are prone to wearing down into the case.Maybe your extremely early oil change intervals have helped avoid that depending on how many hours the motor has done. Guess you have a short season up there.
Best to fit an oil pressure gauge IMO
These look better than Yanmars elbows & cheaper than genuine yammers NZ price, pretty sure 2gm20 has the same mixing elbow:
https://hdimarine.net/
I see I'm repeating what Hpeer said in post #5 but oh well

[Compass790]

Originally Posted by const0022

I had a similar problem, but after quite a few years on a cast iron exhaust elbow on my Bukh deisel. However, I was advised to paint the inside with several cost of epoxy paint. I taped up end with tape and rolled paint in every direction and threw away excess. I think I did three or four coats. Never had a problem again! Had the boat 27 years from new. Now recently faced with a stainless steel exhaust elbow leaking on my motor yacht which is now 10 years old. It's been welded now but engineer suggests replacing section in due course as it's worn thin by passage of hot salty water. 2800 hours on engine though.

Like the idea of painting with epoxy first! Thanks for posting that hack as i imagine a Bukh elbow would be very expensive.

Is your ss elbow that leaked made of tube ( 1.5mm thick ) or sched10 pipe or a casting? What is your current engine?
Just curious.

[thunderhoof]

+1 on the HDI replacement elbows. They are stainless steel, not iron or Al casting and should last considerably longer than the OEM part in the hot seawater environment they live in.

Also, when replacing the elbow make sure the exhaust port of the manifold is clear. I had a build up at this point that was severely restricting gas flow into the exhaust path.

[const0022]

Originally Posted by const0022

I had a similar problem, but after quite a few years on a cast iron exhaust elbow on my Bukh deisel. However, I was advised to paint the inside with several cost of epoxy paint. I taped up end with tape and rolled paint in every direction and threw away excess. I think I did three or four coats. Never had a problem again! Had the boat 27 years from new. Now recently faced with a stainless steel exhaust elbow leaking on my motor yacht which is now 10 years old. It's been welded now but engineer suggests replacing section in due course as it's worn thin by passage of hot salty water. 2800 hours on engine though.

. My present engine, is a Cummins QSB5.9 on my Selene 38 which I bought new in Hong Kong. It is fabricated by the builder in stainless steel and about 6 inch diameter.

[Char99]

Originally Posted by Halifax Sailor

Went to the boat and elbow is cracked. CO monitor goes off so am losing exhaust when I run the motor. Can see what looks like a crack (soot on threads below and on close cooling hose), and elbow is at least 7 seasons old (I have had boat that long). Wondering if there is debate between OEM, replacement stnlss or similiar manufactured products. And as I am in Canada, has anyone sourced in Canada? Yanmar part is 104214-13521 for those who may have some info. I know Yanmar is usually bit more expensive but as this is vital equipment in my mind, would look at OEM original cast steel unless someone has other opinions............

I had the crack appear and I put JB Weld on which lasted one season then the bottom fell out and I had my welder make this from stainless elbow and a piece of pipe. I think he is very clever.
I hope I posted a photo.

[Compass790]

Originally Posted by Char99

I had the crack appear and I put JB Weld on which lasted one season then the bottom fell out and I had my welder make this from stainless elbow and a piece of pipe. I think he is very clever.
I hope I posted a photo.

Well my rating of how clever he is, is dependant on wether he made the part downstream of the threaded elbow out of pipe or tube & wether he purge welded it.
Not common to see polished sched 10 pipe, looks like tube to me.
Still, I don't know from 6000miles away

Nothing wrong with the design idea, it's the materials & execution that have to be right.
Just better to use sched 10 pipe on exhausts rather than tube for longevity.
Lots get made out of polished tube as it looks flash, each to their own I guess.

[TNRivers]

Perkins, not Yanmar....but suffered a near sinking event due to an elbow. Our elbow had been re welded.... but if elbow is bad, the exhaust manifold likely is too. Found we could replace with stainless steel cheaper than OEM. An experienced source to provide a custom fit is Mark at Marine Exhaust of Alabama (they ship and produce in 2-3 weeks).