Funky Muffler; Where did Hat get this??

[Dan Mapes]

So we've had Freedom since '99 and all along I thought the muffler was not doing a good job. But hey, it's a Hatteras so it must be me right? Over the years I have swapped out impellers, boiled out the exchanger and made sure there were no blockages.
The generator which is an Onan 8KW MDKD has run well for us.
So the other day I got fed up and pulled it out. Looking inside, there are two pipes an inlet and outlet. The outlet comes up and out the top. Peeking into the top pipe with a flashlight, I see the pipe ends about an inch from the top of the "muffler"! When the muffler fills with water the exhaust goes in and then right out the vertical pipe without any obstructions. I believe the Centek versions of this type have an outlet pipe that goes quite a ways down into the canister.
It looks like a home brew that Hatteras made up from PVC caps and a coupler.

 

[SeaEric]

It's tough to imagine that it would be somehow more cost effective to build a muffler instead of buying one from a recognized vendor. I guess anything is possible. Are you certain that it's Hatteras OEM? A new replacement from Centek isn't hatefully expensive. I have a good used one on hand (that I will sell cheap) but it's from a 6kw and the connections are probably too small for your application.

 

[Dan Mapes]

Given the heavy duty plumbing I am thinking yes, it was OEM. Note that the pipes have tapped sockets for the grounding screws? Yes, both of the pipes were bonded!
We have a 12x12 Centek on order. I was thinking 10x10 but the folks there recommended a step up since the chamber volume has a lot to do with the performance of the muffler. BTW the pipe O.D. is 2 inch.

 

[SeaEric]

The one I have here is 1 1/2" OD. (If anyone needs it, let me know)
it will be interesting to see what the difference is with the new muffler. Let us know.

 

[Dan Mapes]

Today after boiling out the gen exchanger, painting it and some other things, I mounted the new muffler which is a Centek 12X12 side in top out. The outlet tube does penetrate the canister quite a ways and may be about two inches above the bottom. I suppose I could have butchered the OEM and extended the pipe down into the canister but did not want to mess around with it.

It's MUCH more quiet now.

 

[rsmith]

It's a Vernalift I have one for each gen.

 

[Dan Mapes]

Well, if you think the genny is loud outside the boat, if they are "top out" pull the hose off the top and determine how far down the pipe inside the canister goes. If it doesn't go at least 3/4 of the way to the bottom, consider an upgrade or look for another solution.