Need info on some clamp on mufflers that would be the best for my set up. I have 850sc motors. Don't need to be leagal and still want the roar, just want to ease the sting a little. Thanks, Mike

I Have A Hot Boat Mag From A Month Or 2 Ago That Has About 10 Diff Muffs And Test Results In It If You Don't Get Or Can't Find The Issue Pm Me You Address And I Will Send It To You.

I have (4) 4 1/2 " graffic muffers w/out pump.Asking $600 for all four.

Thanks, but I hope to use some that are non mechanical.

Sent you a pm, thanks!

Has anybody used CMI sound elimination mufflers?

I have run the CMI's on two different boats. First on 1200hp engines. I have them on my Fountain that was 800hp and now is 600hp without the blowers. I LOVE THEM! They kill the noise in a big way at idle which is where most of our troubles are getting into harbors and no wake zones. Very quiet. They will open at about 3000 rpm and will be full flow, no restriction and well ...loud. I like that feature, if needed pull back on the sticks to under 3000 to cruise by quiet when needed. Although CMI claims good to 1200hp I am not so sure. Your engines will work great with those. Give ATECO a call they have a sale through the end of year on all CMI products. First of the year price are going up on CMI. Steel prices.

Use the Drew Marine Shotgun mufflers. I used them for years and they were fine. Plus, when you want to make some noise, like from open exhaust, I cut a little short piece of plastic hose, like 1/8th" stuff, just as long as the plunger that goes in and out of the spring loaded cylinder.
When you hand open the flapper, the plunger comes out of the cylinder, and it's spring loaded to shut when you let go, or at idle when there's little pressure. While it's open, just measure the length of the little rod sticking out of the cylinder, cut a piece of 1/8th" clear plastic hose, take a razor and cut a slot all the way down one side. That way you can open up the hose, and push it onto the plunger, and the plunger won't go back into the cylinder, thus keeping the flap at the back wide open.

I would do this once we left the dock and exited the harbor. Then I had complete open exhaust. If we came into the harbor late in the evening, I would shut off the engines outside of the harbor, and take off the 4 plastic hoses on the mufflers, and it would be quieter again.

If you're interested in that set up, give me a pm, and I'll send you my phone # and I'll explain how it works. You can have the best of both worlds, quiet at the dock, well they're really not THAT quiet, but a little quieter than open headers, and open exhaust out on the lake while running.

Frank

I have Donkey Dicks which works fine off plane, not much muffling on plane but it points the noise downward a tad...

Thanks for the info! So far I think the CMI's look like the best solution. I will give Ateco a call to find out more.