Raw Water Cooling M-25XP

[Leon Sheean]

Has anyone put together a logical sequence of attack to identify blockage on the raw-water side of the mx-25? Is there a schimatic out there?!!

Water flow through the exhaust stopped abruptly on me yesterday and so far I have:

1. Blown out the water intake line (with my air horn, and air seems to move through OK, and water flows back in)
2. Checked the impeller and it is fine and turns when the starter is cranked.
3. I am about to pull the heat exchanger to be sure that raw water flows freely (but it was cleaned by a radiator shop three years ago and only sees fresh water) and my previous impeller did not deteriorate to the point of shreading.
4. But I have never followed the water flow from the heat exchanger; is there a schematic (or better yet photos!) to what ever is next in line, possibly the water-lift muffler?
5. And finally, how does water get from the engine to the exhaust-through-hull and the water injection nipple at the stern?

Thanks.

Leon Sheean
"Therapy"
E 32-200
1988

 

[Loren Beach]

From the model year you cite, I would bet that your engine is an M25XP, 23 hp.
The progression of the water is best diagramed by following the hose, from the thru hull onwards.

I can try to take some notes next time I visit our boat (same engine model), but can assure you that the siphon break hose that goes back to the transom should be peeing out a little stream of water all the time the engine is running and water is also coming out the exhaust pipe.
Reply #2 in this thread, http://www.ericsonyachts.org/infoexchange/showthread.php?t=3404&referrerid=28 , almost shows the piping to the manifold clearly...

As to the exhaust, is the engine still running as before? i.e. no restriction in the large diameter hose? Is any water coming out either the small vent aft *or* the main exhaust?

Looks like some more research is needed.

Best,
Loren

 

[Shadowfax]

I'd suspect that where the outflow from the heat exchanger enters the riser is clogged with muck. Remove the threaded nipple at the riser and run a screw driver around inside the riser to break up the muck. You should run into stuff that looks like thin black mud. Put it back together, start up the boat and more black sludge should exit exhaust.

Hope this works for you, it did for me.

 

[Loren Beach]

From a visit to the family "yacht" today...
The raw water path starts at the thruhull, and thence to the raw water pump at the starboard front of the engine, then back to the heat exchanger entry(same side of engine). Next it leaves the heat exchager cylinder and goes upwards to a "T" fitting, where the smaller hose goes all the way aft to the discharge at the stern. The larger hose goes on, and on our boat, downwards about 3", to the water-injection fitting on the cast exhaust elbow.

That's all there is to the raw water path.

Also, do you have a strainer? Our boat did not come with one, but I added one right after the intake thruhull just to trap grass, leaves, etc...

Loren

 

[Brian K]

Leon, does your E32-200 have "the siphon break hose" that Loren says "goes back to the transom should be peeing out a little stream of water all the time the engine is running"? I also have a 1988 E32-200 and don't recall ever seeing a stream of water "peeing" out the back. I always make sure water is coming out the exhaust pipe, but have never noticed a stream. I'm nervous now and will have to check this out tomorrow. Let me know Leon. You can email me directly at brian.king@us.ngrid.com if you'd like. Thanks.

 

[Loren Beach]

Brian,
Mea Culpa. I forgot that some of the Ericsons had a trick exhaust fitting on their hull that incorporated the small anti-siphon hose, T'ed into the exhaust, just inside the hull.
The part that puzzles me is how having both water exits at the same point on the hull was supposed to break a siphon.

Even on our boat the siphon outlet is only about 2 or 3 inches above the exhaust.

Loren

 

[Brian K]

Ah, thanks Loren. The PO was a very careful owner and told me to always check and make sure the exhaust had water coming out, but he never said anything about a steady stream. Being that I never noticed a stream I was starting to think maybe I had a clog. I need to become better aquainted with my M-25XP and the whole diesel system, it just takes time,,, or a problem! Thanks again Loren!

 

[Loren Beach]

Aha. Here it is

http://www.ericsonyachts.org/infoexchange/showthread.php?t=5967&referrerid=28

This is the prior thread about the syphon break hose...

LB