M-25 Exhaust: Anyone know what this is for?

[Kenneth K]

I'm replacing the exhaust elbow on my '85 M-25. May replace some of the exhaust hoses, too.

Anyone know what this plumbing-type elbow in the exhaust line does? I thought it was something the PO had changed, maybe to fit two hoses of different diameters together, but it seems like I've seen several other Ericson engine pics that had this same feature. Maybe it's an original installation.

Do I need to keep this piece in place. The lower elbow (in the yellow circle) seems to be pretty restrictive in size. Seems like this could all be replaced with just a smoothly bent new exhaust hose......

 

[Pat O'Connell]

Exhaust Elbow

Hi Ken
Interesting.. I'm anxious to hear what you get for discovery on this... In 82 I mentioned to Ericson Technical Support that we had a check valve as you do in our exhaust. Technical support told us to remove the check valve as they had situations where the valve jammed in the closed position. We opened the valve and cut out the check flapper and have had no problems for 35 years. I guess the valve was not needed?
Pat O'Connell
1981 Erison 28+ Universal 5411

 

[Kevin A Wright]

Hi Ken,

That looks like a check valve of some sort. Probably in place to prevent water from flowing back to the engine if you take a big wave from a following sea while under sail, or crank the engine too much without it starting. I don't believe I have one on my 86' M25 (if so it's hiding behind something somewhere).

Good luck

Kevin Wright
E35 Hydro Therapy

 

[Frank Langer]

Can you turn the top off with a large wrench, and look inside? But don't break it!

Frank

 

[GrandpaSteve]

That part is not installed on 1987 Hull#711.

 

[Loren Beach]

FWIW: no such part on our '88 model M25XP.

 

[Christian Williams]

In the plumbing in my house, that would be a clean-out port. Perhaps it allows cleaning of carbon deposits?

Looks kinda handy, if we're looking at the same part.

 

[EGregerson]

Exhaust

I would hazard: a drain to eliminate water from the system for winterizing.

 

[Bill Baum]

I believe you will find that it is a check valve. We had one on our 1982 E33 until it failed, jamming the metal flapper in the closed position. This happened at a someqhat remote location inthe Bahamas. The result was that the engine would start, but not rev above 1000 rpm, and no water came out the exhaust. Fortunately, we were anchored near a very experienced world cruiser whp coached us through a 4-hour tracing of our cooling water and exhaust system to find the blockage. No one knew what this component was. Once we realized it was the blockage, by trying to blow air through it, it took many minutes sitting this component on the stove burner and two large pipe wrenches to get it open and find the jammed flapper door. Fortunately, the hose on the exhaust elbow was long enough to reach the water lift muffler, so we ended up just leaving this check valve out and got along fine. No matter the original Ericson motivation, several diesel experts have told us it was a bad idea. It's now four years later, we continue to cruise the Caribbean, and have never regretted removing that check valve.

 

[Pat O'Connell]

Exhaust Check Valve

Hi Bill
Sorry that you had that grief with the flapper. Long time ago but as I recall I was able to cut out the flapper with a little Stanley Tools Hacksaw Blade Holder after I opened the cover plug.. That was a pretty easy fix but I don't think the boat was much over a year old and the cover plate was not heat cycled many times by the exhaust (yet.)
Best Regards
Pat O'Connnell
1981 Ericson E28+ Universal 5411

 

[jarnold67]

Check Valve

In my E26-2, I have a similar check valve. In addition to the large opening in the top of the valve (that you can see in the picture), there is a small threaded holding pin on the side that contains the pin on which that the "flapper" or disk swings.

In the course of the boat overhaul, I pulled out the valve and cleaned it up. I opened up the valve (by placing the valve in a vice and using a plumbers wrench, if I recall correctly) and found the disk to be free and resting on the bottom of the valve. When I took out the holding pin, and after looking closely at the disk, I saw that the pin that was to hold the disk in place had corroded away (it was carbon steel). I cleaned up the valve with a wire brush and reinstalled the disk with a piece of copper rod that wouldn't rot in the seawater. After cleaning it up after testing to ensure the valve worked properly (the under the faucet test), I put it back into the system.

That said, I just now went back and reviewed the Westerbeke Technical Manual. It does not call out for a check valve, and instead clarifies the need for one or two high loops before and after the muffler. Similar guidance is provided by Beta for their engines. Perhaps this was a "belt and suspenders" solution by Ericson? If it works properly, it does no harm and probably some good.