Exhaust noise

Not sure this should be listed under the engine topics, but I figured if it should someone would help me out. I finally finished restoring my boat last summer and took it out a couple of times. It has a Mercruiser 5.7 that exhausts thru the transom, below the swim platform.

My wife hates how loud it is and is insisting I do something about it. I?ve found a few different muffler tips and one ?slip in silencer?.

Does anyone have any experience/recommendations for making the boat quitter or any of these mufflers?

My current exhaust has a shutter system in the tip and external flapper. If I remove the tip would an external flapper on a new mufflered tip be sufficient to keep the water out?

Thanks
Bill

Re: Exhaust noise

If you have the Y pipe that goes to the outdrive, you can hook up the factory exhaust with 2 elbows and some rubber hose and clamps. That would make it real quiet, and has just as much power as your loud set-up.

Re: Exhaust noise

I currently don't have a Y pipe. My pipes come straight off the exhaust, have a couple bends and exit out the transom. Since I just put the engine in last year, I really don't want to have to pull it again.

Re: Exhaust noise

Slip in silencers will do almost nothing. You would be quietest with the exhaust exiting below the waterline but you can buy mufflers to put inline before the transom. Down pipes from the transom will help much more than a slip in unit. There are internal flappers available.

I know you don't want to, but the best solution is definitely to have it go through the outdrive. If you can't do that then try calling BoatPipes and seeing if they can help you. All of their stuff is for inboards so it would have to be custom but it sure makes an inboard quiet.

Re: Exhaust noise

honestly the easiest solution is to yank the engine and install a Y pipe.... there ARE water lift mufflers you could install if you have room but you're looking at quite a bit of work and expense with elbows and hose and mounting.... just hook up the stock exhaust and cap the tips on the inside of the boat... all the cool 'twice pipes' looks without the side effects like divorce, alimony, and child support.