I was wondering is there anyway to make my exhaust louder on a 1985 merc outboard?

Question

It is a 125 merc outboard inline 6cyl, i was thinking i could drill some small holes in the back of the exhaust housing to let the exhaust come out before it went through the prop. Is this a good idea or would it hurt performance?

Answer 1

why would you want to make it louder in the first place? are you deaf? or do you want to make other people deaf? do you want to be recognized when your out on the water? do you want to attract attention? what do you want to do? my answer is that this is not a good idea!!!!!

Answer 2

If you figure it out .. keep that   )(*@!#$^!@)(*&!#$  boat off of any body of water near me ....

Answer 3

You want to increase the noise volume?

Go ahead and drill lots of big holes. Maybe the engineers that designed that engine were all wrong about back pressure issues.  Maybe they had no concern about an engine that wasn't a nuisance to those around it.

Maybe, but I doubt it.

Answer 4

me being a harley guy.... i can appreciate a nice exhaust tone.... but me not being an experienced boat guy.... doesn't the exhaust get let out under water anyways???  you want the fishies to hear you coming better or something?

Answer 5

ROFLMAO at "thru-hull exhaust" for an outboard!  

More at stake than just backpressure on the exhaust.  

The exhaust housing on two stroke engines are "tuned" -- they are a specific length because they count on the sound waves of the echo of a preceeding powerstroke to block the fresh air/fuel charge from escaping through the exhaust ports before the piston closes 'em off.

Short-circuit the exhaust, you end up with less fuel & air in the chamber, more unburned fuel & oil in the exhaust, lost horsepower.  

Coked up cylinders, sticking rings and eventually, catastrophic piston failure.

Answer 6

why ?

Answer 7

Most places have a noise law. But if you want to cheat you would need to install a Thru hull exhaust. They do make a mechanical switch that you can also install that switches from thru hull to out the prop also  You are talking a lot of money for a six popper! Not worth it!!!

Answer 8

Don't drill anything as water flows out there also> It's a 6 if you open the exhaust it will sound like a rice burner> You can take the ex==and go threw the transom with a straight ex> it will make noise> But it's a 6 and will sound like a 6> Keep it quiet> Enjoy the quiet & people won't look at you for excessive noise> I have Opened up 8 cyc they sound nice> Not a 6?? Unless it was a V6 then you have 2 ex===?

Answer 9

First, this could be illegal as in violating state and possibly federal noise pollution regulations on marine engines.  

Second, no one wants to lose their hearing from an obsencely loud outboard on the lake.

Third, this is several thousand dollars of precision equipment that runs on VERY tight tolerances.  You don't go drilling holes in it or tinkering with stuff ignorantly because you want to.

Fourth, this has a dangerous ability to possibly cause a fire or explosion if the engine overheats too much because of the exhaust system severely overheating.

Edit:

Yes, most marine engines vent the engine exhaust through the water either through the prop hub, caviation plate exhaust pipe, or transom pipes at water level.  Only certain racing boats and big engine jet boats have exhaust systems that are above water.

If you've ever heard a large outboard or inboard/outboard backfire or run on high RPM out of the water, its extremely painfully loud.

Answer 10

Yes, certainly. Mix 1 part Karo syrup to 9 parts gasoline into your tank. Let it sit overnight. Your engine will run much louder, and will actually make a deeper, "throatier" engine sound.