E35-2 exhaust replacement

[Ffejs]

Quick question. Haha. Have a1979 35-2 (555) with the yanmar 2qm20 and the standpipe type cast muffler has disolved. Through my research, a replacement type muffler would need to be custom fabricated, if i can even find someone with those skills. so no bolt on replacements.
what have others done when this hurdle is experienced?
If going the water lift option my concerns are the waterline and exhaust exit level being about the same, anybody have experience using a simple elbow directly at the exaust manifold with high loop in the water line with anti siphon valve or should i have fabricated pipe that turn the corner and rises up under the starboard bench lazarette, similar to the path of the standpipe, puttin the location of the elbow and water introduction high as possible, then with rubber exhaust tubing dropping down to the water lift?
The exhaust port is also very high on the ericson. Is a simple high loop in the exhaust tubing from the water box to exit port the solution to prevent the residual un exitied water from flowing back into and further up to the exhaust manifold?
Thanks in advance to any input, even a redirect to an older post of same problem. I tried a search and only found other size ericsons and atomic diesel fixes

 

[Nick J]

HDI marine makes high quality replacement exhaust parts. They are a fantastic company to work with.

QMKIT Stainless Steel Exhaust Kit for Yanmar QM Series Engine - HDI Marine

These HDI Marine items replace Yanmar PN 128370-13600 / 128270-13600 / 124070-13520 / 128370-13610 / 104214-13531 AND Yanmar PN 128370-13600 / 128270-13600 / 124070-13520 / 128370-13610 / 104214-13531

hdimarine.net

 

[Ffejs]

Thanks for the link. Do you have this on your E35? Does the lift to the elbow fit with the small space from manifold to the bottom of cockpit floor?
Does the purchase include all that is seen in the pic?

 

[Pete the Cat]

To answer your original question (if I understand it correctly) that is the way it is usually done, though the loop is generally after the water lift muffler. There is generally a vent in the raw water between the heat exchanger and the elbow. I am sure there is a diagram of this somewhere on the internet.

 

[Nick J]

Yes, everything fits but I have a 3YM20 in my 35-3, so its different than your configuration. The link I sent has everything included in the pic. I changed out the nipple between the elbow and the fitting that bolts to the back of the heat exchanger with a longer unit. This raised my injection point more than 14" above the water line and 12" above the water lift muffler which made it so I didn't have to install a vented loop. Here's the link to my post about the upgrade:

Exhaust Rebuild?

Segue has a new exhaust system! Everything from the exhaust manifold to the back of the boat has been replaced. Even the plywood the muffler sits on was replaced. I went with Shield corrugated exhaust hose to help with the bends below the cockpit sole, on to the thru hull, and to the outlet...

ericsonyachts.org

 

[bsangs]

HDI marine makes high quality replacement exhaust parts. They are a fantastic company to work with.

QMKIT Stainless Steel Exhaust Kit for Yanmar QM Series Engine - HDI Marine

These HDI Marine items replace Yanmar PN 128370-13600 / 128270-13600 / 124070-13520 / 128370-13610 / 104214-13531 AND Yanmar PN 128370-13600 / 128270-13600 / 124070-13520 / 128370-13610 / 104214-13531

hdimarine.net

Confirming what @trickdhat said. I bought a full exhaust replacement for my Yanmar 3GM30F from HDI and it's perfect.

 

[Nick J]

I just reread the original post and realized I misunderstood what you were asking about. I'm not familiar with a standpipe exhaust system so I googled it and found this:

Tartan style, stainless steel standpipe muffler – moyermarine

moyermarine.com

Maybe it's a more direct replacement that won't involve too much rework. That being said, I'm really happy with my exhaust set up. it's worked flawlessly so far and it looks like it would remove more heat quicker than a standpipe configuration. The waterline issue in relationship to the exhaust and water injection point can be worked around through vented loops if you have room. Either way, let us know how it goes. Exhaust systems are interesting and it's really cool to see what others come up with.

 

[Ffejs]

I just reread the original post and realized I misunderstood what you were asking about. I'm not familiar with a standpipe exhaust system so I googled it and found this:

Tartan style, stainless steel standpipe muffler – moyermarine

moyermarine.com

Maybe it's a more direct replacement that won't involve too much rework. That being said, I'm really happy with my exhaust set up. it's worked flawlessly so far and it looks like it would remove more heat quicker than a standpipe configuration. The waterline issue in relationship to the exhaust and water injection point can be worked around through vented loops if you have room. Either way, let us know how it goes. Exhaust systems are interesting and it's really cool to see what others come up with.

Thanks for info. I did contact and talked to the guy. He says his unit will only work with the atomic 4. Says what i got will most likely need to be fabricated one off. Stressed whatever i do, Exhaust elbow and water inlet levels need to be same if not higher than original unit. Its all based on boat make and motor configuration. Pointed to this site to see what others have done with like boats and motors.
im thinking with the water lift system, the addition of strategically placed loops in the raw water line and route of exhaust out the boat will eliminate the need to get the exhaust and raw water inlet as high as possible

 

[Mr. Scarlett]

As stated above, see if a stock mixing elbow will work.
When I repowered my last boat the stock mixing elbow would have to protrude through the cabin sole so I bought and cut stainless pipe and elbows and made this.
Not the best pics but it worked well and as far as I know it is still in service. The bellows goes between a short, threaded length of pipe and the section shown. After the "U" turns, water is injected to mix with the exhaust (after going through a vented loop), the pipe changes to hose and down to the waterlift muffler (in/out both on top). From there the hose goes straight up, does a full loop, and downhill from there to exit below the transom. Vetus makes an exhaust gooseneck that may oy may not have helped in this case.
All in all I was quite pleased with how well it worked out. I was replacing an Atomic 4 so there was nothing to copy. I have no idea if I should have factored in back pressure or not, performance seemed fine to me.

Edit: the length of the vertical section was to have the water mix with the gases above the waterline.

 

[Nick J]

Stressed whatever i do, Exhaust elbow and water inlet levels need to be same if not higher than original unit

I would caution against assuming the original configuration was good. There's a lot of factors that go into these systems and in 2023 there's even more information and past experiences to draw on. @Kenneth K posted an awesome guide in post 2 of exhaust rebuild link above. I found my configuration benefited from a few small tweaks. Worse case scenario, you validate a good design. The risk of getting it wrong is flooding your engine with sea water and causing some major damage or creating a syphon and sinking (extreme case, but still possible)

 

[Ffejs]

Gonna go with the HDI system. 9” lift with a higher loop in raw water line with siphon vent. Down to a water lift then up over a loop higher than the transom thru hull out the rear. Gonna look just like trickdhat. Your post of the exhaust rebuild confirmed some thoughts of a fix. And easier yet, all parts seem to be mass produced, no need for custom fab and the headache of mixing metals i know nothing about.
Ill post pics when done.
thanks for the advise