noise reduction

[Gus Mortimer]

I have been researching sound deadening materials. what I have seen (that will fit on the inside of my cowling) is a spray or mat like rubber stuff mostly for deadening the noise from vibration. <br /> Does anyone have any thoughts on where most of the noise coming from my motor is actually coming from? Think it is vibration noise? <br /> I am putting some spray rubber on now. Has anyone else tryed to reduce the noise on their outboard?<br /><br /> P.S. I have an 82 90h L6 merc

 

[NOSLEEP]

Re: noise reduction

Just a few months ago I did a similar sound <br />deadening to my 2004 Nissan 6 hp 4 stroke.<br />I used a material that is used on automotive bumpers<br />and related parts to cover them for shipping <br />to help prevent damage. I doubled it up by using<br />Kent spray on adhesive.Then cut panels to fit<br />the sides and the top,used the same spray on<br />adhesive to glue it to the inside of the cowling.<br />I have had no problems to date and sure seems alot<br />quieter. Also I was worried it might cause over<br />heat problems but we have had hot weather and the<br />motor has run all day with no side effects.

 

[Gus Mortimer]

Re: noise reduction

what is this material and where did you get it? <br /> I was also worried about the overheat issue due to the insulating properties of most sound deadening materials, good to hear that you have had no problems there. <br /> Also how thick is this material. I have very little clearance.

 

[NOSLEEP]

Re: noise reduction

You should be able to get the material from any<br />local body shop. When doubled up it is around<br />1/4" thick. There are different types, I stayed<br />away from the foam that had the bubble stuff<br />attached to it.

 

[JasonJ]

Re: noise reduction

Dynamat would get it done. I am going to get some and apply a couple of layers on my Merc.

 

[Hooty]

Re: noise reduction

1. The primary noise source is the air intake.<br /><br />2. The insulation/silencing material you put inside the cowling will not have any effect on the engine temperature as the engine is water cooled.<br /><br />3. Don't install anything inside the cowling that will come loose and get sucked into the engine or will absorb fuel and become a fire hazard.<br /><br />c/6<br />Hooty

 

[Gus Mortimer]

Re: noise reduction

I looked at dynamat but after a few calls to the place that has it to find out what sizex were available and how much it cost(not cheap!) I then drove all the way across town to pick it up and they did not have the size I needed. so I am not going there anymore. <br /><br />Jason: If you are going the mat route look into a materil called B-Quiet look at the "brown bread" it has better damping properties at higher temps than dynamat, here is a link or cut and paste. http://www.b-quiet.com/brownbread.html

 

[phatmanmike]

Re: noise reduction

i have one question about the origonal post...<br /><br />why is your merc I6 loud in the first place, mine is ungodly quiet...way more quiet than any evinrude i own...<br /><br />im just curious

 

[JasonJ]

Re: noise reduction

The brown bread looks interesting, too bad it is sold out. Its also too bad it can't be purchased in smaller amounts. My motor isn't that noisy, but if it can be quieter then that would be a good thing.

 

[Gus Mortimer]

Re: noise reduction

PHATMAN: I dont know if it is loud compared to an evinrude or not. It just seems quite a bit louder than the boat I used to have (inboard 4banger). <br /> If yours is "ungodly quiet" do you think I could have a problem? It is hard to talk over it in the upper rpm range.<br /> oh by the way the spray I used did little or nothing to quiet it down.

 

[Mercury140-I6]

Re: noise reduction

Honestly, I don't think there is an ouotboard made (2-stroke) that you can talk above without yelling from 3000rpm's and up. All I have is the original batting that came with it.<br /><br />Craig

 

[Ronald1]

Re: noise reduction

I have a 1977 Evinrude 35 that is VERY loud. It is bolted to a 16' johnboat. I have a 1970 Evinrude 60 that is very quiet. It is bolted to a fiberglass trihull.<br /><br />The question is how much of the difference in noise can be attrubuted to engine refinement, and how much goes to hull material/construction?

 

[Gus Mortimer]

Re: noise reduction

when I got this motor there was no batting or anything inside the cowling, just the metal wrap. I think I am going to put some more "stuff" in there yet.

 

[KCLOST]

Re: noise reduction

If you have enough room to apply it, I would try the egg tray foam that they use on the top of matresses... As long as it doesn't get in contact with anything above 250F you shouldn't have any problem using that. But it's a matter of how much room you have... That stuff is the best sound proofing material I know of, in addition to being pretty comfortable to sleep on ...<br />All you need is a can of 3m super 77 or 90 to apply it to a cleaned surface...<br /><br />Walmart sells the stuff pretty cheap in the bedding section. You might check it out. It can be cut easily, and even trimmed down in thickness if you have a clearance issue...

 

[paul watki]

Re: noise reduction

I thought you might be interested in another product called Mass Loaded Vinyl.This is a product used in the soundproofing industry and has the effect of deadning soundwaves. I understand it comes in different thickness and as it could be bonded to the internal cover, would not present any dramatic reduction of air volume around the engine. I stumbled across this product on a soundproofing forum, http://supersoundproofing.com <br />Its some MLV and a pot of glue for me.