TOPIC: Why do Mercury's have a louder exhaust than omc's

I was at the lake and a simlar vintage boat with a Johnson 35 horspower engine was out there 2 both early 60's engines. his exhaust was about half as loud as my Mercury. Is there exhaust through the prop or at least under the water? I know my Merc exhausts above the water line.

silencer on the carb of omc non on a merc.it is not the exhaust you are hearing the difference in.

With the exception of some racing motors, most outboards, including your Merc, exhaust UNDER water. The reasons for noise differential are many, and it's rarely an apples-to-apples comparison. Your Merc probably has an exhaust relief above the waterline, which really only comes into play at idle speeds, when the exhaust can't force its way out under water. Johnrudes have a similar relief midway up the rear of the motor leg. Both brands eventually had a baffle system to cut down on noise coming out that relief.

A Johnson or Evinrude fatty V4, or even the late 1950s 35 and 40hp twins, have extensive systems to deaden sound through the use of a double wall exhaust housing, rubber dampers, fiberglass cowlings, etc. Mercury didn't do quite as much with the whole sound thing as OMC. The were the first to have an exhaust tuner, which had the effect of directing the exhaust right into the lower unit, but it also changed the note of the sound with a bit of a tuning effect. So it might be fewer decibels, but at a higher pitch. Mercury's metal cowlings also did less to quite the powerhead noises, fiberglass inner blankets not withstanding...

Bottom line, it's partly perception, partly reality, partly depends on the motor...

Thanks The only place I had seen exhaust come out was in the hole just nelow the pan. and a lot of it comes out there I guess the rest comes out the port just above the prop.
I like the way the merc sounds but then again I am an old hot rodder. The guy with the Johnnyrude was the one that said the merc sounded nasty in a good way. You could here it sing at full throttle all across the lake.

I agree with all said. Also OMC had thick fiberglass hoods, insulation, carb silencers (maybe)..where a great amount of 2 stroke noise comes from. Mercs just a inside thin wrap of insulation, usually destroyed over time, removed, and a thin sheet metal wrap, that resonates noise too. Little if any carb silencers.
And this! " the merc sounded nasty in a good way". DARN RIGHT! I can listen to 2 type motors all day, a stroker big inch Harley at idle, and any IL6 MERC! Especially at about 1/2 throttle, where it..(mine anyway), simple GROWLS, waiting to punch to WOT!!

want to here a real loud merc try a mark20H conversion(toilet bowl)

Dave - NOTHING like the 20H. Simply the BADDEST sounding outboard EVER! You haven't lived until you've gone in to turn one with 11 other bouncing, buzzing B's all around you (preferable just behind you).
- Scott

YEP ON THE 20H! My older brother had one on a Baby Switzer, and the neighbor at the lake had one on a Hydro. Non toilet bowl, but still way to cool for this, then 5 year old kid! I also never did hear live, a IL6 "Stacker", but seen vids, and what a monster!
Also gotta say the new motors are SO quiet, its , well, no good to me. Neighbor bought a center console, big Suzuki back end. He's at the launch dock, I see the pee stream coming out of it..(looking for the front, standing on the dock) and say, "that got some kind of electric water pump on it?" He says, ITS RUNNING! Had to go to the back and look for exhaust...WAY too quiet for me!

If you like open exhaust of old motors, come to the Tomahawk meet of the AOMCI. Open exhaust for four days of running. 20H's, 4-cyl/w pipes, sometimes 6 cyl/w pipes, and even a looper 6 cyl. Next year the dates are July 31, Aug 1-4 at Tomahawk Wisconsin.

Running a Mod Merc with megaphones is not for the faint of heart.
Ran mine for about 30 min. at the Silver Lake Meet & couldn't hear anything for Hours after. Remembered to bring everything but the ear plugs. The thing literally hurts your ears.
Tim

Here ya go..