no more fouled plugs

[Joesailboater]

I recently acquired a 74 Newport 30. The original owner kept the boat pretty much as it came from the factory down to the vintage avocado cushions and yellow bubble glass sliders on the galley compartments. No upgrades, no modifications. As you would expect, the boat needs some TLC and a lot of cosmetic attention. The original Atomic 4 still ran!!!
The boat had been left on the pier for three years before I got it with nothing done to it so I was very surprised to get the thing cranked at all. It had some fairly pronounced valve taping and after several weeks of Marvel Mystery Oil, It seemed to quiet down. At first, She was very hard to start so I rebuilt the carb (which was so full of goo that I couldn't imagine how it ran at all) and pulled the plugs and found them all to be very fouled. New set of plugs, rebuilt carb. and more Mystery oil treatment and she cranked right up. I was surprised that I didn't have to replace points and condenser but it started fine after about three seconds of cranking.

She ran fine for the first outing but the next day it was back to the hard starting again. I pulled the plugs and found them to be just as fouled as the old ones I had just replaced. I decided to get the hotter Autolite plugs and see if that would help. Nope!! Still fouled.

So, after much reading and thread chasing I decided that I had a back pressure problem. As I said before, this boat is vintage, no upgrades so the exhaust system was all original (new hoses being the exception).

The hot pipe exits the manifold above the waterline in my boat and turns to port and down to meet the bottom of the old copper muffler below the waterline. The cooling water runs from the back of the manifold to the TOP of the copper muffler and I assume showers and cools the exhaust. The main exhaust hose leaves the BOTTOM of the muffler and carries the water and exhaust to the transom.

This system all looked to be in good shape and had (I assumed) served the previous owner well for many years. I thought it was odd though that he would keep such a large stash of plugs on board.

Anyway, The exhaust and cooling water seemed to exit the transom as it should so I figured I had some blockage somewhere. I wasn't quite ready to tackle replacing the hot pipe or the manifold just yet so I continued reading. The exhaust pipe dipped down after it left muffler and then rose to meet the exhaust port at the transom. My first thought was that this was normal because it must have come from the factory that way. Nothing else on the boat had been changed. BUT....I was still fouling plugs and I couldn't find my system explained or pictured or discussed anywhere so I didn't know if it was correct. I was starting to wonder if it had been installed that way or was this the only modification the PO had made. It didn't follow the logic of any system I could find. It all seemed to be too far below the waterline and hold too much water in the downward bow of the pipe. The exhaust had to push a lot of water out of a long uphill tube.

I decided to try to emulate the configuration of the exhaust pipe on the water lift muffler and raise it above the water line as soon at it left the muffler. I raised the exhaust pipe as high as I could just as it left the muffler and let it fall the rest of the way to the transom. I probably raised it a good 18 inches and the rest of the pipe drained naturally to the exhaust port. I figured it was holding at least a quart of water in there before I raised it.

I started her up and she immediately ran smoother and much to my surprise, I have not had one fouled plug since. I pull them frequently to check and to continue my Marvel Mystery oil treatment and they continue to be dry and toasty looking. Just that little bit of back pressure relief changed the way she ran that much! I still can't believe this old engine runs as good as it does after all these years. If only the PO had figured that out years ago. I imagine him going through plugs every outing.

I was able to find a diagram of my particular installation on-line and I will try to attach it. I have still not been able to identify my muffler but it still works and even better now.

[Administrator]

Great story, Joe.

I think Don has mentioned elsewhere that he figures upwards of half the A4 fleet is fighting back pressure problems.

Maybe one of these days, he'll regale the forum with the story of the boat he bought as junk due to chronic overheating problems, only to discover that the plumbing was installed backwards. Interestingly, he helped a guy at our marina with a similar problem in a brand new Tartan. The yard guys couldn't believe their eyes.

Bill

[hanleyclifford]

What you appear to have done is straighten your exhaust system and eliminate the need for the engine to expend energy "batching" out the water. You have thus realized an efficiency benefit. The down side is that you have eliminated a water safety feature which may have been intended to keep water out of the engine. These two design features are always a trade off. I suggest that you establish a protocol in which you shut off your water intake thru hull several seconds before shutting down the engine.

[ndutton]

Joe,
Glad to hear you resolved your issue. I'm intimately familiar with the Newport 30 of your vintage and it's exhaust system. I've carefully read your post and studied the attached diagram. Before I comment, a question: is the drawing as you found it or did you make the cross-outs and notes yourself to more accurately represent your original system?

[tenders]

The exhaust on my Ericson 32 is set up very similarly, except that my engine is a V-drive and is turned 180 degrees from yours, so the exhaust runs down the starboard side of the boat instead of to port.

The muffler, which has a "J&B Marine" manufacturer's sticker on it, is mounted *quite high in the boat* just like you've tweaked your installation, so it's all downhill from the muffler output to the transom discharge. It is not a "water-lift" arrangement as is often referenced here.

This has been a good arrangement as far as I'm concerned and I'll be interested to see what others think about it.

I can easily imagine the engine choking on its exhaust if it had to blow all the accumulated water uphill. Maybe some mechanic took things apart once and reassembled one fitting pointing down instead of up...and everything else just happened to fit?

[Joesailboater]

Well I figured I would end up with more questions to ask after the pros weighed in.
Niel: The drawing I attached is from a downloaded owners commissioning manual. The hull # on that boat was close to mine and better yet, the diagram almost matches my setup exactly (save the fuel tank, Mine is 90 degrees the other way). The notes and drawings are not mine but it's very close to an exact match.
Hanley: The raw water intake shut off valve takes a bit of acrobatics to reach. I worry about water running back into the exhaust but please tell me if my thinking is flawed.
My motor is mounted high enough so that the exhaust exits to the hot pipe above the waterline. The hot pipe then drops to the bottom of the muffler. The water pipe that runs from the top rear of the manifold to the top of the muffler is all above the water line and will partially drain back when the motor is shut down.

I am not sure if the left over water in the exhaust hose will get back into the manifold when the high point of the hose is lower than the back of the manifold where the hot pipe bolts on. Both the high point of the exhaust hose and the back of the manifold are above the water line if that makes a difference. The un-expelled water in the exhaust hose will find its level I suspect BELOW the manifold when I shut her down.

Please let me know if you still think I need to crawl in there and close the raw water intake before I shut down. If it looks as if I do, Is there another fix?

Thanks for your expertise.

[Joesailboater]

And yes Niel, I crossed out the name of the muffler that the diagram owner had replaced his with. Mine looks just like the diagram. I also do not have the anti-siphon loop on my water hose leading to the top of the muffler. I have considered installing that but if you have suggestions, please post! I'm new at this.

[ndutton]

OK Joe, here's my take.

The drawing, without the handwritten modifications is just as I knew the system up to 1973 when I left their employ. The hot pipe originally went to port and UP to a riser type muffler (you said yours went down). The factory muffler was through bolted to the cockpit seat riser and the top of the muffler was very near the underside of the port cockpit seat. The original riser/muffler assembly was actually a single weldment made of ferrous metal which likely explains why yours was replaced and reconfigured.

As originally designed, the hot exhaust gases went up to the muffler, seawater from the engine was introduced near the top of the muffler (no mixer like our waterlifts), the exhaust then exited the muffler on a downhill run to the transom. It was an excellent system for keeping water out of the engine.

So, I'm certain yours has been modified to what sounds like a waterlift system by someone who didn't fully understand how one works, hence all the spare spark plugs on board. Since you now have a waterlift, you need to approach its repair/redesign as if your manifold outlet was below the waterline. Even if it's above the waterline, it isn't by much, maybe inches and that will change as the boat heels under sail.

There are excellent threads on this forum describing proper waterlift systems complete with drawings. After reviewing the written description of your current system I'm more than a little concerned about it's ability to keep the engine dry. The exhaust exit out the bottom of the muffler, the water injection directly into it, no mention of the exhaust hose looping as high as the deck before going down to the outlet, all these things are a concern. Rearranging what I suspect is a poorly modified system is not the way to go either. The engine may run better but keeping the water out under varying conditions is critical.

Now, I've said all that without seeing your system (pics are always a plus) so don't necessarily consider this treatise as gospel. If it were me, I'd still hold the option open for going back to the original standpipe system but I have the advantage of experience with it. I'm not saying a properly designed and installed waterlift system is inferior, but rather the standpipe is still one of your options.

Unnecessary trivia: The crossed out, handwritten W.H. Den Ouden description of the muffler on the drawing is actually a Vetus muffler (not the factory original). W.H. Den Ouden was the company that handled all the Vetus products at the time and a bunch of other boat related stuff.

[hanleyclifford]

Joe - I re-read your posts and I think I have made a useful sketch of your system. This needs to be to be done as an "elevation" (to use an architect's term) with the water line drawn in and all components placed in their relative positions. With this in mind it appears that you have done nothing more than reduce the available on board reservoir for un-expelled water. The muffler in all likelihood has adequate capacity to hold any residual water after shut down without compromising the manifold. What makes your installation favorable from this standpoint is your above waterline engine exhaust. Of course waterline position is not the real consideration in this matter. What really matters is the injection height, the water discharge height, the maximum water volume that needs to be "batched" and the "head" against which this must be done. Waterline becomes a consideration when the possibility exists that water will syphon thru the hull valve into the system after shut down. Hence all the interest in anti - syphon loops. But if you shut off the water every time (as I do) the anti - syphon loop becomes irrelevant. Inasmuch as you prefer not to shut that water off each time I recommend that you use an anti - syphon loop unless you are dead certain that no such effect is possible in your installation. Also may I call your attention to an idea our Brother Pater posted: it is possible to divide the discharge water between the exhaust system and overboard discharge. The exhaust system does not require all the water to cool itself to a safe level - so why waste precious engine energy and efficiency "batching" and pumping water uphill when some of it can be harmlessly pumped overboard directly? Thanks for bringing this matter up and I am very interested in any further thoughts you have on this. Regards, Hanley

[Joesailboater]

Hanley: The exhaust still batches the water as it exits the transom but only at idle. It sprays when RPMs are higher. Also, are you speaking of a vented loop in the exhaust hose or in the water injection hose between the manifold and the muffler or both?

I suspected that what I had was an early version of a water lift muffler and I take it from what Neil is saying, It sounds like I need to get some elevation into the pipes somewhere. This muffler looks like what you describe as a standpipe but the hot pipe definitely drops and enters at the bottom and the exhaust hose exits just at a 90 degree angle from it.

Would a redesign of the hot pipe satisfy the issue of keeping water out of the engine? I have considered bringing the hot pipe out at a 90 from the block until it cleared the bulkhead and then turning it up to just under the port cockpit seat and then back down to the bottom of the muffler. I could get about 6 to 8 inches of hight above the manifold (I think) before it turned back down.

The existing exhaust hose does not loop all the way up to the underside of the deck before it starts back down. It rises to just about the level of the manifold. That puts about a 12 to 18 inch rise in it (I guess I really need to measure all of this) from where it leaves the bottom of the muffler and then a gentle slope down to the transom.

An elevation showing the water line and the pertinent components would be helpful I agree. I may attempt a crude rendering later after I take some measurements.

[roadnsky]

...Please let me know if you still think I need to crawl in there and close the raw water intake before I shut down. If it looks as if I do, Is there another fix?

A quick answer to your question is YES.
In addition to re-considering/re-designing your exhaust system (a proper long-term solution IMHO) you could install a three-way valve in a more easy to reach location to "shut off" your intake water flow. (See pic)
I did this myself to avoid having to remove cushions and a hatch to shut off the thru-hull.
It is not only a quick fix, but gives you a convenient way to pump in acid or vinegar for a cleaning as well as anti-freeze if you do winter layup.
Mine also gives me the added bonus of being able to throw some additional hose on the end and put it in the bilge to use the engine as a pump out in the event of a major leak. (Hope to never put this to the test though)

[hanleyclifford]

Joe - This is where Neil's hands on experience and first hand knowledge is better than my theoretical input. He mentioned that the hot section and muffller rose high enough that the injected water ran downhill to transom. No doubt it was also high enough to exclude a following sea. It did not have to drive water uphill. These are both huge considerations. Of course the section must have been substantial and required good support. If you are of the mind to start over and redesign your system the whole discussion needs to shift gear. Try to develop an elevation of your situation with the measurements, or perhaps you might like to go back to the factory installation? You've got the platoon's attention! Regards, Hanley

[ndutton]

Joe
For your reading pleasure (credit to Concord for the original post):

http://www.pearson35.com/p35articles...s/Exhaust_.pdf

One last comment on the standpipe system, it's virtually impossible to backflood the engine with prolonged cranking/no start with this system, one advantage over the waterlift.

[Joesailboater]

Jerry you have me thinking. I can run the raw water hose through the bulkhead into the quarter berth, install a valve then return the hose into the engine compartment and into the strainer. That will be much easier to reach quickly. I can use my soon to be installed "T" fitting in the hose between the strainer and the water pump for drawing antifreeze and acid flushing.
And I hope I never have to use the my A-4 for an emergency pump either....oh well....sail boating is not for the faint of heart.

[Joesailboater]

Thanks to all for your help. Still not sure of the fix but at least I know what problems to look for.

Neil, the link is not functional...."not found" Can you re-post it as a quote? I think it may contain some valuable answers for me.

By the way, I wondered if I would run into any Newport builders out there. I could come up with a hundred more related questions. I have already come to really enjoy working on this boat as much as I enjoy working on my Atomic-4. I get nothing but positive comments about both.

sorry for the thread creep.