Muffler question

Blaise · Mar 14, 2011

The water is injected into the exhaust at the exhaust elbow, not at the muffler.

emilbec · Mar 14, 2011

I am curious here. . .When I recently repowered the mechanic said I did not have a water lift muffle, but rather just a muffler. Was that the way it came from the factory or did someone mess with setup?? He added a water lift muffler and left the other muffler in place for increased quiet.

Jim Legere · Mar 14, 2011

emilbec said:
I am curious here. . .When I recently repowered the mechanic said I did not have a water lift muffle, but rather just a muffler. Was that the way it came from the factory or did someone mess with setup?? He added a water lift muffler and left the other muffler in place for increased quiet.

The H37C came stock with just a stainless steel horizontal muffler. And its not the most quiet exhaust. When I have to replace (as Ed S. recently did) I will probably go with a Vetus waterlock muffler. Which has a drain, unlike the original.

sandpiper10471 · Mar 14, 2011

My H33 had a water lift muffler. I suspect it was original equipment. No idea now what make it was. And there was no drain. As Jim mentioned, the 37C came with a horizontal Haven't really noticed much sound reduction.

Blaise · Mar 15, 2011

I have a vetus waterlift muffler (22yrs old) that does not have a drain. My exhaust with my 3gm30f is very quiet.

emilbec · Mar 15, 2011

Thanks. I know I replaced the original muffler about two years ago. My mechanic was surprised there was no water lock muffler on the boat considering how low to the water the exhaust is. Frankly I am more comfortable with the water lock. Have to think about draining it come fall next year. I hope things are a bit quieter with the new engine. the old 3QM30 really put out a racket

Paul F · Mar 16, 2011

Please read about my experience last year with the 33. The title is "Warring Bad Exhaust Design" that says it all. You must have a water lift muffler and a loop in the exhaust hose to prevent water from backing into the engine and destroying it. The original exhaust layout along the bottom of the boat is bad as it allows water to directly enter the engine. here is a link to the thread.
http://forums.hunter.sailboatowners.com/showthread.php?p=775279&highlight=exhaust

Johnb · Mar 16, 2011

As so often happens this discussion piquied my curiosity. I found what I think is a really good article.

http://www.practical-sailor.com/marine/waterliftmuffler.pdf

John T1594 · Mar 17, 2011

Muffler

Both of my sailboats (1980 H30 & 2000 H340) have a horizontal "muffler" installed behind the engine. The engine and muffler were above the loaded waterline and this design was factory installed.
On my old boat H30 (2QM15), the original muffler was a SS, horizontal muffler with a 2" inlet and outlet. It began to leak after about ten years and Hunter Marine advised me to replace it with a Primex fiberglass muffler replacement from Marine Mufflers (http://www.foreandaftmarine.com/MC-0300001.htm). When I installed the new muffler, it was clearly marked to position it horizontally but with one side facing up. I have to believe that there were internal baffles to trap the water and prevent back-flow. The natural flow and pressure of the exhaust forces the water up and out of the exhaust pipe. When winterizing the engine, I always waited until the exhaust turned the color of the antifreeze solution, ensuring that the muffler was protected. My newer H340 (3GM30F) has the same horizontal, fiberglass muffler installed by the factory. It runs quiet.

sandpiper10471 · Mar 17, 2011

I would suggest spending the extra few dollars and get a water lock rather than a water lift muffler. Less chance of backflow to the cylinders and comes with drains for winter prep.

sandpiper10471 · Mar 17, 2011

Perhaps you are right. I have just spent some time googling to find the difference but was unable. Perhaps I was mislead in the past or didn't understand. I thought the waterlock prevented flow back through the exhaust whereas a water lift just silenced the system by passing gasses through a water filled container. I am sure someone will enlighten us one way or the other.

Nereussailor · Mar 18, 2011

Just a couple of quick questions on mufflers and exhausts.
1. What is the difference between a muffler and a silencer?
2. Can a water lift muffler exit the boat at or below the waterline?
3. Like sandpiper asked, What is the difference between the water lift and the water
lock muffler?
4. Most of the mufflers I found have inlets/outlets that are too big. Is there a reducer that will work to fit my exhaust hoses?

I tried the link to the practical sailor article, but it said that the link wasn't found.

Ed Schenck · Mar 19, 2011

Here is a similar muffler story, mine, from last summer: http://forums.hunter.sailboatowners.com/showthread.php?p=720014&highlight=muffler . Long story short, I had Centek make me a custom fit muffler.