Exhaust Flange Tightness

[GorgeSantana]

My water lift muffler connects directly onto the exhaust flange. Every 180 degrees of rotation of the flange onto the muffler lines it up with the manifold holes. I think I have to go to the next 180 degree point as I'm getting some exhaust fumes in the engine compartment.

I'm wondering how much force I can apply while rotating this flange before I create a problem?

I have a brand new Moyer flange and have cleaned up but not recut the tapered threads on the muffler. I'm imagining that these tapered threads will lock up pretty hard at some point. If that's not when the muffler is in the right location, I'll have to back it off. Then I figure I'll get a leak around the threads.

Should I be using any sealant on the tapered threads?

[Don Moyer]

Having tapered pipe threads line up can be quite a challenge. I'm not sure
what you mean by the muffler connecting directly to the exhaust flange, but
you can usually get some of the "swing" you need on each end of a nipple.
In any case, you probably won't damage anything by using a bigger wrench and
more muscle to get things to line up.

Although I have heard of others who have found a high temperature sealer,
I've never had to resort to sealer in the several hot sections I've replaced
over the years. Perhaps someone else will weigh in with a sealer
recommendation.

Don

[sunnnnseeeker]

Can you post a picture of the water lift muffler on the flange? There must be pipes between which should give you enough rotation to get another 180 degrees. If the pipes are already very tight and still leaking, I suggest getting new pipes, especially if you know they have many years of age on them and they are rusted. The threads in the flange do have a limit and if the male threads (on pipe) bottom out in the flange before the threads are tight I would get a new pipe. You could also grind 1 or 2 threads off the end of the pipe if the threads bottom out before they are thight in the flange. Double check that the gasket is good between the flange and the manifold and check that the manifold surface is flat so you have a good seal surface for the gasket.

[GorgeSantana]

muffler picture

I tried again and got another whole turn on the flange. This seemed to close the gaps and resolve the leaking exhaust.

If I had to do it again, I'd mark a line on the flange and the pipe before disassembly to show the final position choices. Then I could turn it till it was tight and in a correct position.

Attached is a picture of the water lift muffler. It's completely welded closed so I can't inspect the inside. The exhaust comes in lower than the water inlet and the mixed exhaust/water outlet. There must be an internal pipe that passes up through the center and keeps the water from coming back into the engine.

It's working fine now. Quiet, cool and smoke free...... now onto the vibration that's occurring when I have the prop running at medium speed.

This forum is great......

[tenders]

That's just like my muffler except that I have a fiberglass-wrapped pipe that runs out the manifold allowing the muffler to be installed just forward of my side lazarette about 18" away from the engine.

I like this design. It's quiet (at least I think so!) and it appears to me that it would be very difficult to fill with seawater while cranking. The water drains downhill out of the muffler whether or not there's exhaust pressure to push it out.

But is this what's called a "water lift"? I thought a "water lift" muffler was more along the lines of those Vetus plastic things that are below the level of the engine, and require exhaust to blow out the seawater.

[GorgeSantana]

I don't know if this muffler style is called a water lift. I may be using that term wrong. I really don't know how the internals are baffled and ported.

Don sent me a sketch from a Tartan muffler that looks similar on the outside. It really is more of a mixing of water and exhaust than a lifting.

If you didn't see it, check the thread I titled Fuel Goo in the Fuel section. I talked about how this muffler clogged and there's a picture showing all of the debris I emptied out of it.

[tenders]

> I really don't know how the internals are baffled and ported.

I don't know either.

But in my mind's eye the inside of this design has a smaller pipe that goes most of the way up the middle of the outer canister, and has a little "umbrella" or "hat" welded to the top of it. The exhaust is directed up this pipe and it escapes into the canister between the top of the pipe and the hat. The raw water dumps onto the "umbrella" and splatters down between the pipe and the canister, cooling both, but prevented by the umbrella from going into the smaller pipe. The cooler exhaust and the water then drain out the bottom of the canister.