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E29 with A4- exhaust head scratcher.

cityhix

Junior Member
Hello!

I have a '71 Ericson 29 with the original Atomic Four. I've been having issues with seawater back flowing in to the exhaust manifold. This has occurred both under sail and at the dock. The exhaust outlet in the transom is roughly at the water line on a starboard tack and 3-4" above the water line at the dock or motoring in flat water.

The flow of raw water through the exhaust system is a bit of a puzzler. Water leaving the heat exchanger goes to a tee. From the tee, one leg goes to a vented loop and then dumps in to the exhaust elbow at the aft of the exhaust manifold. The other leg goes toward the transom and tees back in to the wet exhaust after passing through a gate valve. This entry point is just before the transom, aft of a loop in the wet exhaust. So to summarize my hot raw water has two points of entry in to the wet exhaust, one at the manifold and one just before the outlet at the transom. As part of my diagnostics to determine how raw water is back flowing in to the exhaust manifold, I'd like to understand why the system was set up this way. I will be replacing the Vetus anti siphon valve and did locate some suspect exhaust hosing and will be replacing the whole run.

Any insight?

Thanks!
 
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Kenneth K

1985 32-3, Puget Sound
Blogs Author
Others will know more, but my understanding is that the smaller tube that runs aft to the exhaust thru-hull IS the vent for the vented loop. Sure, it may pump water out while the engine is running (it will pump out more water if your injection elbow is clogged). But, with the engine not running, it acts as a siphon break.

Absent a vent, a one-way check valve would have to placed atop the vented loop. But check valves can stick, and then the loop no longer prevents your boat from sinking (which would also require 1. the raw water thru-hull being open, 2. one or more missing vanes on your impeller, and 3. the injection elbow being below the boat's waterline-boat heeled or not).
 

toddster

Curator of Broken Parts
Blogs Author
It doesn't sound like the stock exhaust system. All the ones I've seen or heard of had the standpipe exhaust as per the manual posted on this site. (I think it's the last page of the manual, IIRC.) With the standpipe, there shouldn't be any way for seawater to back up into the exhaust.
 

Afrakes

Sustaining Member
Stand pipe

I agree with Toddster about you needing a stand pipe muffler. Stand pipes however are not without their failure points. If the center exhaust pipe rots off at the very top then water can get back into the exhaust manifold. It's important that the top of the center pipe is always above the cooling water. The cooling water enters the stand pipe at its lowest point and flows up to the exit which is located just below the top of the center exhaust pipe. The rubber exhaust tube, with water and exhaust gases, then runs downhill to the exhaust thru-hull. Never had any experience with a water-lift muffler exhaust system on an A4. Can you take pictures of the set up?
 

cityhix

Junior Member
I'm confuseed by terminology re: exhaust standpipe. I see products (like the Vetus NLP) that are referred to as a water lift muffler and appear designed to be installed inline after the exhaust elbow (with the raw water inlet). Does this serve the same purpose as a standpipe?
 

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
I'm confuseed by terminology re: exhaust standpipe. I see products (like the Vetus NLP) that are referred to as a water lift muffler and appear designed to be installed inline after the exhaust elbow (with the raw water inlet). Does this serve the same purpose as a standpipe?

It can be confusing at first. Thing is, you always need to keep in mind the basic "flow" of the exhaust system. There will be different shaped mufflers and the amount of rise in the elbow where the hot exhaust gases enter from the manifold will vary a bit depending on engine make/model.
Here is a link from Betamarine.
https://www.betamarinenc.com/exhaust-design/

For instance, if you look thru my blog entries from 2018 forward, you will see our "Vernalift" water lift muffler. Same function as the different brand in the illustration.
The "standpipe" design still routes the cooling water into the exhaust in a similar fashion. In all of these, the water has to have sufficient volume to cool the gases and keep them from melting the exhaust hose that goes to the transom. It's an old and proven design, and our old factory-install exhaust hose was finally starting to leak a bit of water late in 2017. That's nearly 30 years of usage (and 2300 hours per the Hobbs meter).

I know little about the legendary A4 engine, but am pretty certain that this part of the installation is very similar to any small sailboat auxiliary.

Some pix will help, too.
 

Parrothead

Member III
Standpipe vs. waterlift

Here is a graphic comparison between a standpipe and a waterlift exhaust system. Moyer Marine carries both in their online catalog in stainless. A properly designed and installed standpipe system has less backpressure than a waterlift and cannot backflood water into the engine. Also a standpipe system does not require an anti-siphon loop even though one is shown in the drawing. There's no harm in adding one, another level of protection. The waterlift elevation drawing is missing the anti-siphon loop by the way.
Standpipe elevation.jpgStandpipe detail.jpg

Waterlift elevation.jpgWaterlift detail.jpgWaterlift function.jpg
 
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cityhix

Junior Member
I removed all of the exhaust system this evening, from the manifold to the through hull in the transom. The system as I acquired it has no muffler of any sort. I have a SS elbow that comes directly off the manifold, rising up several inches and then turning down at 45 degrees, terminating about 6-8" below the manifold. This fitting has the inlet for raw water. From there, reinforced rubber hose runs aft past the battery bank, exiting between the transom and the cockpit structure before looping up in a full 360 degree loop and exiting the transom.

I wish i could see how the exhaust was originally configured on the E29. I can't see how to properly install a water lift muffler which should be near centerline and below the manifold. This would Require locating it in a very tight space over the shaft and forward of the battery box. Similarly, a standpipe system would require some tight turns through a crowded space in to the port lazarette.

I simply can't figure out why the system I have decided to stop working after 2.5 years with no apparent failures or changes.
 

Christian Williams

E381 - Los Angeles
Senior Moderator
Blogs Author
I think typically the water lift muffler is off to the side, as on the 32-3 and the 381, adjacent to he prop shaft.

M25.jpg
 

toddster

Curator of Broken Parts
Blogs Author
It's difficult to get a clear photo of the original configuration, since the standpipe was concealed within a plywood baffle in the sail locker. Here's a couple of shots taken early in my ownership, when I was trying to figure out the system. Creative wiring and vibration damping system as installed by the Previous Owners.

The hot exhaust exits the manifold and takes an almost immediate 90 degree bend through the bulkhead into the sail locker. Then another 90 upward into the standpipe. This is all inside a plywood box tabbed in at the forward end of the sail locker. The standpipe is bolted to the bulkhead between the galley and the sail locker.

IMG_0351.jpg

Water from the heat exchanger enters the standpipe at the bottom and fills the outer jacket, cooling the exhaust gas which runs through the inner pipe. Water and exhaust mix at the top and exit through a pipe and hose that descends to the stern through-hull.

IMG_0347.jpg

They don't last forever - part or all of this had obviously been replaced at some point and it was in fact all rotted out under the insulation when I bought it. Since replaced with the stainless steel unit from Moyer Marine. Which is arranged a bit differently. But you could also take the original drawing to your local machine shop and have another one welded up for a couple hundred bucks from black iron pipe.
exhaust.jpg
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
I removed all of the exhaust system this evening, from the manifold to the through hull in the transom. The system as I acquired it has no muffler of any sort. I have a SS elbow that comes directly off the manifold, rising up several inches and then turning down at 45 degrees, terminating about 6-8" below the manifold. This fitting has the inlet for raw water. From there, reinforced rubber hose runs aft past the battery bank, exiting between the transom and the cockpit structure before looping up in a full 360 degree loop and exiting the transom.

With a 360 degree exhaust loop, it seems unlikely your seawater in the manifold is traveling all the way from your exhaust thru-hull. I'd be checking out that exhaust elbow. You should post some pictures. Some elbows inject the cooling raw-water only on the "downhill" side of the elbow (this prevents raw cooling water from running down into the manifold, but makes the top of the elbow the hottest part of the system). Other elbows, like some Universal elbows and the Yanmar elbow I replaced mine with, inject water into the "uphill" side of the elbow (keeps the top of the elbow much cooler). These elbows require separate inner chambers (one for exhaust gasses, one for water) until the two mix on the "downhill" side of the elbow. A rusted-out or cracked inner chamber could allow cooling water to run back down to the manifold.

Water Jacket.jpgUNV-200372.jpg


By the way, how did you discover you had raw water in your manifold? The only stories I've ever heard are: water in the manifold---> water enters an exhaust valve --> water gets in a cylinder ---> engine gets hydro-locked and destroyed.
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
Wow, that is a head-scratcher. Unless there's an obstruction in the exhaust tubing?

You sure it's raw water and not anti-freeze/coolant in the manifold?
 

cityhix

Junior Member
Wow, that is a head-scratcher. Unless there's an obstruction in the exhaust tubing?

You sure it's raw water and not anti-freeze/coolant in the manifold?

I did find that the section of reinforced rubber tubing just after the stainless elbow was close to failure with delamination of the internal layers. Perhaps the was causing an obstruction preventing full evacuation of exhaust gas and raw water? So I shut the motor down and a hose full of water runs back in to the manifold.

I'm 100% sure its sea water. No fluorescent color and it is salty to taste. Plus, I can't bear the thought that it's antifreeze.
 
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cityhix

Junior Member
So I tracked down a water lift muffler from my local sailboat salvage yard and bought it with the hopes of making it work. In my E29, I'm severely limited in space aft of the motor. Our house batteries are located in a fiberglass pan approx 12 inches aft of the aft bulkhead in the engine compartment. I have attached a photo of my stainless exhaust elbow and the new/used muffler. I'm considering shortening up the pipe between the elbow and the muffler and having these welded together. If I cut away some of the aft bulkhead in the engine compartment, I should be able to fit the whole assembly. I would devise a way to provide extra support for the muffler so it isn't hanging off the manifold. From the outlet of the muffler, I would run tubing up under the cockpit and out the transom with a loop above the waterline.

Am I on the right track?

I'm not sure why this photo is rotated. Please rotate 90degrees to the right.
 

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toddster

Curator of Broken Parts
Blogs Author
I'm trying to imagine getting a stiff exhaust hose to bend onto that outlet pipe in the few inches you'll have available under the quarter-berth... maybe. :confused:
And will there still be room to work on the stuffing box, which is in that 12" gap? Engine compartment blower and vent hoses, battery cables... a lot going on in there.
I'd still suggest adding an immediate 90 degree turn into the sail locker, just behind the galley cabinet. Lots more room. Not easy to work up in that corner, but it can be done. Your spine might not ever be quite the same shape again though. :rolleyes:
 

cityhix

Junior Member
I'm trying to imagine getting a stiff exhaust hose to bend onto that outlet pipe in the few inches you'll have available under the quarter-berth... maybe. :confused:
And will there still be room to work on the stuffing box, which is in that 12" gap? Engine compartment blower and vent hoses, battery cables... a lot going on in there.
I'd still suggest adding an immediate 90 degree turn into the sail locker, just behind the galley cabinet. Lots more room. Not easy to work up in that corner, but it can be done. Your spine might not ever be quite the same shape again though. :rolleyes:

True, it's a tight space. Any harm in having a hard connection between the exhaust elbow and the muffler?

Currently nursing a bound up lower back.
 
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toddster

Curator of Broken Parts
Blogs Author
Dunno... the standpipe system is all hard connections. I was a bit concerned about a vibrating motor attached to a bolted-down muffler, so I added some rubber bumpers (appliance feet from the hardware store) into those bolt assemblies. No issues have arisen that I'm aware of. The previous owner simply didn't bolt the muffler and left it all hanging from the manifold flange. (In fact, I couldn't find any holes where the factory should have bolted it, either.) AMF Swim Fin inserted for vibration damping, as shown above. :rolleyes:
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
I rebuilt my my exhaust system (M25 diesel) in 2017. Here's the best article I've read on the subject:

https://www.goodoldboat.com/reader_services/articles/Marine_exhaust.php

While it's more than you'll likely want to know, it also has it's limitations. In the end, we are all limited by our particular engines and the particular engine spaces we have in our boat.

Figure 4 is the key figure in the article. I'm am sure there are many, many sailboats in which the recommended dimensions described in Fig 4 simply can't physically be achieved. Still, at least it gives you and idea that "part A" should be higher or lower than "part B" to the extent allowable.

Most every Ericson diesel installation I've seen uses a combination Riser/Elbow in the exhaust. My take is that the "Riser's" purpose is to elevate the point at which raw cooling water is injected back into the "Elbow." The importance of this seems to increase as the placement of your engine becomes closer to (or, likely, further below) the boat's waterline. I believe "raising" the elbow serves 2 purposes: 1) it decreases the likelihood that "siphoning" through the raw water line can flood your engine and 2) it provides a way that a "low mounted" engine (ie, at or below the waterline and, thus, close to the hull), can still empty its air & water exhaust mix "downward" into a waterlift muffler (which must be situated below the water injected elbow).

If those are true, I see three potential cautions with your design. 1) Unless your engine is located above the waterline, your riser probably doesn't rise high enough (measured from exhaust gas entry point to water injection point) to pass the "siphon break" / "won't flood your engine" criteria," 2) unless your engine sits very high above the hull, I don't see how you'll have enough space to locate that muffler as far below the riser as your picture shows, and 3) every exhaust installation I've seen uses flexible hose between the exhaust riser and the muffler. Our engines (mounted on rubber engine mounts) vibrate and shift position too much to have a long, rigid pipe connection like that. Even Catalina's, which often have long, horizontal pipe runs, typically use a short silicone "hump hose" to allow movement between the rigid exhaust riser and the rigid exhaust pipes.

All of these potential problems might be fixed by a higher riser and a flexible hose run to your muffler. I'm not trying to be critical (and other users can tell you if I'm off base--this could be a gas vs diesel thing). These are just the issues I encountered when redoing my exhaust--shown here: http://www.ericsonyachts.org/infoex...-Riser-Elbow-Replacement-with-Support-Bracket

Good luck.

BTW, my neck was sore for weeks after redoing my exhaust. I could only lay on my right side facing aft in the quarterberth during the installation. Must have held my head up to one side like that for hours. Maybe add in some $$ for a chiropractor along with your parts budget.
 
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Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Ken, Thanks much for the GOB link. Our ship wright went to some trouble to lower the water lift muffler relative to the top of the exhaust mixer elbow on the Beta25.
This article helps explain why.
I put a picture of it into my blog, also.
 
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