1984 force 85 hp sound deadening fix

[KnarfOH]

Yes, I am asking a question AFTER I already did something. LOL.

I installed some sound deadening material after the factory stuff went bad several years (or more ago).

Please check out the pics and tell me if I made a mistake.

Pics HERE

I have been running without anything and you get used to it, just hoping to soften the sound some. I am taking out later but wondered if someone else has tried the same solution (or another one?).

The one thing I kept reading was - once the factory foam stuff starts flaking, GET IT OUT FAST !! It can be drawn into the carburetors and then I would be really sorry.

Give me an opinion please.

 

[stubtail]

Re: 1984 force 85 hp sound deadening fix

That stuff looks good! I had replaced my original foam with a replacement high temp fuel/oil resistant foam of equivalent thickness, cut to size and glued it in with contact cement. That works well everywhere except directly in front of the carbs (I don't have any intake baffles), as it quickly succumbed to the solvent-like nature of the fuel that spits out of the carbs, and the foam started to pull from the cowl. To avoid a potentially disasterous situation, I installed a 0.032" thick aluminum shield to the cowl, preventing the foam from being drawn into the carbs, and it also keeps fuel from soaking into the foam.

That being said, I could have saved myself some extra grief by doing what you did. Looks like it will work well. Good job!

 

[SkiDad]

Re: 1984 force 85 hp sound deadening fix

let us know how much it helps sound and about how much it costed you.

thanks

 

[KnarfOH]

Re: 1984 force 85 hp sound deadening fix

That being said, I could have saved myself some extra grief by doing what you did. Looks like it will work well. Good job!

Just got back in the last half hour. I know everything is relative since this is an engine that sits on the back of the boat as compared to an inboard that is buried under a cover that in itself offers sound deadening properties, but I believe it worked to reduce some of the sound. Was it it significant? Probably not signiicant, but I do believe it helps.

I looked at products I suspect were similar to what you probably used and I was concerned about deterioration around the motor. Google the name (Dynamat) or look for it on Amazon. One thing I liked it is how the amount of material in the box was exactly what I need to fully line the top and sides of the engine cowl. I had one sheet left over (12" x 36") and I cut that in half and lined the sides again so that area has 2 layers of the material.

Curious. What I ended up buying cost me $57. When I looked at other material, it was much more expensive. What did you end up thinking about the noise reduction for the material you bought? And do you mind me asking how much it cost?

Reason I asked was because the material I found that I thought was suitable cost a lot and the application process, i.e. cutting, gluing, etc., was going to be a lot more complicated then for the product I bought.

let us know how much it helps sound and about how much it cost you. Thanks

$57 for 4 sheets that were 12" by 36". The material is some type of tar like material that is VERY sticky with the aluminum covering. You peel away a waxed paper to expose the adhesive side. I don't know if you noticed, but in one of the picture I took it shows a shippers tape dispenser usually used to tape up boxes. LOL. Amazon sold a roller that you could use to roll out the material once you apply it by hand. The roller was about $16. I used the heavy duty tape dispenser as a roller and it worked great and I saved myself $16. I hand pressed the materials into the corners, etc.

Just Google "Dynamat door kit" and you should find it easily. Also, my pics include the box with the product number, etc.

 

[tater76]

Re: 1984 force 85 hp sound deadening fix

Wow! another use for Dynamat. My truck is entirely lined with this, inside doors, headliner, floor, back wall, etc. You could drive through a bell making factory and not hear a thing LOL! Plus, in the winter the cab stays warmer longer, and cooler in the summer. My only worry for your application would be excessive heat on the material? Great idea, I may have just enough left over to try on one of my 55's. Anyone who has torn out the old stuff then run all day knows the difference any sound deadening material makes. Thanks again!

 

[KnarfOH]

Re: 1984 force 85 hp sound deadening fix

My only worry for your application would be excessive heat on the material?

I checked the engine cowl right after operating the boat yesterday afternoon. In a properly running engine, it does not get as hot as you are probably thinking. To be honest, I would not be surprised if the material gets much hotter when it is exposed to heat from the sun beating down on a vehicle. I could easily touch my boat engine after operating it. I cannot say the same for the metal parts of my vehicle after it has sit outside in the sun. You are right to worry about that, but I honestly don't think it will be a problem.

 

[jerryjerry05]

Re: 1984 force 85 hp sound deadening fix

Nice looking job.
My question??? How thick is the product?
It looks like it's a liner and not very thick.
My foam disapeared a LONG time ago.
It's not that loud and it's way more work than I wanna do.J

 

[emoney]

Re: 1984 force 85 hp sound deadening fix

Looks good and if it works, great. I was just in West Marine and noticed they sold a sound-deadening material, too. I could've used that on the little jet boat I had. I didn't check to see how much it was. Kudos!

 

[KnarfOH]

Re: 1984 force 85 hp sound deadening fix

My question??? How thick is the product?

The aluminum top is 4 mil thick. The elastomeric butyl (what I called a tar like material in earlier post) is thin. Specs and description can be seen HERE

It looks like it's a liner and not very thick.

It is not very thick. And calling it a liner is probably a good description. Its original use is to primarily reduce vibration noise so consider it a dampening material. I don't remember the original material blunting the sound very much.

My foam disapeared a LONG time ago.

A lot of people have privately commented that the original FOAM LINER started deteriorating many years ago too (on a boat this old). What distressed me was mine was turning into a crumbling dust, etc. I got the advice to get it out of there IMMEDIATELY once that started happening because if it got sucked into any of the carburetors then I could have a serious repair problem cleaning them.

It's not that loud and it's way more work than I wanna do.J

I had a difficult time locating a product that looked similar to what was originally installed in the engine cover and had properties that permitted it to deal with noise, gasoline, oil and heat. Everything I saw was expensive; had to be cut to fit: etc. You can cut this with a razor knife or pair of scissors. My engine cover has bends, etc. but it is not sculpted, so basically all my cuts were straight lines which made it easy to use this material. It took me 15 minutes.

I was like you originally - I just removed the old material and lived with the sound. This does dampen the sound, but outboards are loud even with the sound dampened down. I can easily see where someone would get used to it and not worry about the sound at all.

An earlier post questioned how well this material would deal with heat. The faq sheet I linked to above says it will handle 300 degrees fahrenheit.

 

[RRitt]

Re: 1984 force 85 hp sound deadening fix

way back when i was younger than today ... I used 3/8" neoprene. same stuff they make wetsuits from. I had dual 85's hanging off the back of a CC fishing boat. The neoprene made a dramatic difference. There was no doubt at any rpm that it was much, much quieter. Of course the neoprene was difficult to install. Had to be cut just right and needed a high quality cement. I used the kitchen countertop contact cement from home depot.

 

[Jiggz]

Re: 1984 force 85 hp sound deadening fix

I wonder if you also did the lower cowling? I think if you did you will see a significant decrease in noise. As for the fuel spilling when the engine is raised. I think a piece of aluminum sheet can be used to ensure it flows straight downward instead on the side of the cowling.

 

[KnarfOH]

Re: 1984 force 85 hp sound deadening fix

I wonder if you also did the lower cowling? I think if you did you will see a significant decrease in noise. As for the fuel spilling when the engine is raised. I think a piece of aluminum sheet can be used to ensure it flows straight downward instead on the side of the cowling.

I am the original poster. I was not the one experiencing any fuel spillage issues. My fuel has never spilled. I only attempted to replace the old foam material that was part of the original engine cover. The cover is also what I am referring to as the cowl. Not sure what you mean by "lower cowling". The material I used has dampened the noise. How significant? I have no idea.

Did you look at my pictures? Link in my first post. Or better yet, you can see the engine HERE

 

[Frank Acampora]

Re: 1984 force 85 hp sound deadening fix



Undoubtably you have seen this cover but I never showed the inside. It is lined with yoga mat that I picked up at a yard sale for 4 dollars. It is similar to wet suit neoprene. Notice the 1/4 inch nuts and bolts replacing the rivets. The two halves of the cover are glued together with epoxy and rivets replaced with the bolts. That in itself eleiminated much of the noise. 'Course, in the later Force cowls, they are one piece so bolts are not necessary.

 

[Jiggz]

Re: 1984 force 85 hp sound deadening fix

I am the original poster. I was not the one experiencing any fuel spillage issues. My fuel has never spilled. I only attempted to replace the old foam material that was part of the original engine cover. The cover is also what I am referring to as the cowl. Not sure what you mean by "lower cowling". The material I used has dampened the noise. How significant? I have no idea.

Did you look at my pictures? Link in my first post. Or better yet, you can see the engine HERE

Oh wow! That is one heck of a clean engine.

 

[Eazzy]

Re: 1984 force 85 hp sound deadening fix

I used B-Quiet on mine i think it was about$30.00 for an 12in.x 12ft roll