Sound deadening

pdqford

Cadet
Joined
Oct 28, 2010
Messages
21
What works good for replacing the sound deadening under the hood of my early 80’s Chrysler 75 HP?
 

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tg3690

Lieutenant Junior Grade
Joined
May 7, 2019
Messages
1,070
The sound deadening qualities of the foam lining your hood are marginal at best. The bigger problem is that foam is disintegrating into small pieces and getting sucked into your carbs. I would not run it again until all that foam is removed. When I removed the foam from my hood I could not tell much difference in sound. If you want to replace it with something else maybe somebody on here has an answer for that.
 

DunbarLtd

Petty Officer 1st Class
Joined
Nov 8, 2016
Messages
357
I just used 3/8" thick closed cell foam from a local foam shop. Doesnt make it any quieter. Im not sure why they put foam in there in the first place. I went the cheap route and used foam but they sell dynamat that specifically is used for sound deadening in cars. But its expensive and Im not sure how much it would quiet it down.

Its a 2 stroke. Its gonna be louder than any 4stroke out there. I dont mind the sound myself. If you really want to quiet down a 2 stroke...buy a 4 stroke :)
 

Nordin

Commander
Joined
Jun 12, 2010
Messages
2,596
I have used old sleeping mat (kind of closed cell foam) and glue it in the hood.
Not expensive at all and I feel like it make the engine quieter.
 

8ender

Seaman Apprentice
Joined
Nov 1, 2018
Messages
39
I stuck down some cheap sound deadening material (the heat resistant type with the reflective coating) inside the cowl of my 45hp Chrysler and it quieted down the racket it made especially at idle.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,089
Unless the foam is fuel/oil resistant(not sure they even make that??)??
I wouldn't put that in there as you'll have the same problem.

Sierra used to sell sound deadening material.

I just took mine out and threw it away and didn't replace.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
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50,426
the company that makes most sound deadening material for marine and industrial use is soundown.com . they have heat/chemical/etc resistant products for absorbing sound.
 

The Force power

Commander
Joined
Feb 3, 2019
Messages
2,350
Some shops sell oil absorbent pads, I bought the thicker once at cut them to seize / glued it place (makes a world of a difference)
 

pdqford

Cadet
Joined
Oct 28, 2010
Messages
21
Many Thanks for all the replies.
You have all been very helpful.
I now have a direction and materials to explore.
And all winter to get it done!
 

The Force power

Commander
Joined
Feb 3, 2019
Messages
2,350
Whatever you use..........make sure you use a good industrial adhesive (you don't want it to come loose and get sucked in the Carbs.)
 
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