using dynamat on underside of cowling?

[wrestler20]

has anyone tried using any kind of dynamat or other types of sound deadening material on the underside of their outboard motor hood/cowling? I have a 200 johnson looper that just seems to be a bit louder than other outboards that i have heard and was wondering if there was any kind of improvements that could be made so i can at least talk to the person sitting next to me. thanks for any info, <br />Steve

 

[kd6nem]

Re: using dynamat on underside of cowling?

I would think that DYNAMITE would only add to the problem short term, but help in the long run... Actually I'll be interested to hear what not only works but also lives awhile in that environment. I hear that a few motors had optional intake silencers which really helped too.

 

[red10]

Re: using dynamat on underside of cowling?

i would think that dynamat would not dissipate heat very well and hold it in because it seems to be like asphalt and gets hot

 

[wrestler20]

Re: using dynamat on underside of cowling?

i have wondered about that and would opt for the high heat version that is supposed to go under the car hood. I have also seen kits from overtons that are just a foam padding with some type of aluminum or something on one side. some of my friends cowlings already have foam underneath them from the factory, but mine has nothing there. My biggest concern is the heat retention issue. steve

 

[Hooty]

Re: using dynamat on underside of cowling?

Be careful and don't put anything inside the cowling that could come apart and get sucked into a carb.<br /><br />c/6<br />Hooty

 

[Franki]

Re: using dynamat on underside of cowling?

I looked under the hood of a new e-tec the other day.. and it looks like they use some form of tar based product like Dynamat...<br /><br />then again, that engine was so unlike anything I've seen before, that its probably not a good example.<br /><br />rgds<br /><br />Franki

 

[rickdb1boat]

Re: using dynamat on underside of cowling?

Never tried it, but how bout a few coats of something like rhino Liner. Not sure of heat resistence, though...

 

[vidar]

Re: using dynamat on underside of cowling?

Hi! it will not get any warmer than cooling water temp... plus the engine will suck in air to cool.... and highest temp will be after shutdown.... soo the glue must tolerate aprox:195degree F...spesialy if the colour of cowl is black... cause of sunwarming in addision...sorry bad spelling...

 

[rickdb1boat]

Re: using dynamat on underside of cowling?

Works on a bedliner that sits in the 90+ temp around here in the summer. Bet it gets pretty hot on there, when absorbing the heat of the sun..

 

[seahorse5]

Re: using dynamat on underside of cowling?

Do you have the factory installed sound deadening foam inside the motor cover, or did someone remove it?

 

[Franki]

Re: using dynamat on underside of cowling?

My old Johnsons fiberglass deadning was in a very sad way when I got it, so I pulled the lot out..<br /><br />right now, the inside of my cowling is smooth fiberglass, no sound deadning at all, and thats on a 100HP.. so its pretty noisy..<br /><br />So I am watching this thread carefully..<br /><br />I'm going to try some sort of tar product if i can find one that doesnt' cost the planet and looks like withstanding the heat.<br /><br />rgds<br /><br />Franki

 

[CaptJB]

Re: using dynamat on underside of cowling?

This topic is of great interest to me also. I have a pair of 175 Mercs, 1992 vintage, sitting on the transom of my 25 foot WA fishing boat. The noise level is not bad, but I would like to make it even quiter. I put up a post on the Merc section on this topic several weeks ago, titled Noise Reduction.<br /><br />Based upon responses to that topic plus my own research, I plan a two prong attach of the problem. I plan on building a cover over my engine motor well and lining the under side with sound deadening foam, the idea is to stop sound waves from coming straight at me from the engines.<br /><br />The other part of the potential solution is to put more sound deadening foam in the cowlings. There is some there now, but I will measure to see if additional can fit. One wasted area is the emergency rope starter stored in each cowling, I will remove and replace with sound deadening foam. It will be necessary to ensure that no foam can come loose and get sucked in to the air box. I might try to make a screen for over the airbox inlets.<br /><br />I will follow this tread to see if anyone has additional info.

 

[wrestler20]

Re: using dynamat on underside of cowling?

i have a 92 200 gt johnson and it doesn't have any kind of foam on the underside of the cowling. I don't know if it ever did, because it doesn't look like anyone ripped it out or anything. There is definitely room under there for something though. I just havn't decided if using the outboard kit from overton's is worth the money or not if i can just use some dynamat or something. I can't believe that nobody else on here has tried it before. I was hoping to see that it had already been done by someone. I am going to look around in some different places and see if i can find anything that may be comparable to use. Thanks for all the replies though. If i do it, i will post the results this summer after everything thaws out up here. Steve

 

[vidar]

Re: using dynamat on underside of cowling?

HI! i used the 3/8 thick foam/foil plates on my 140 suzy and it workes just fine.. total cost: 20$...