Noisy operating noise

[Daviemcc]

Recently replaced a Volvo AQ-170 with a <br />Volvo AQ-151C this motor operates way noisier than the previous.<br />There is at present a spray on insulation on the engine cover, but it is doing very little to reduce the noise.<br />Is there a better spray or insulation available to replace the original (1979)material?<br /> Thanks in advance<br /><br />Davie

 

[glasply1]

Re: Noisy operating noise

For my engine (chev 350) cover I attached 1/2" noise control barrier material from West Marine. For 1/2" X 32" X 54" its about $80. 1" thick material is about another $20, but be sure you have enough clearance for it on all sides. I don't know how well the glue will hold the added weight of the 1" thick material.<br />I had enough left over to put a second layer on the vertical portion of the engine cover facing forward towards the cabin, which is where I thought the extra material would do the most good. Seems to be doing a good job of holding down the engine noise. <br />I attached both layers with 3M spray adhesive, applied to the material and the engine cover. Carefully compare the different 3M adhesives before you buy it. Its been mounted for over 2 years and is holding up well. Good luck with your project.

 

[Daviemcc]

Re: Noisy operating noise

Thanks Glasply<br />Your suggestion is the way I will go.<br /><br /><br />Davie

 

[sail&power]

Re: Noisy operating noise

Thanks for the info. I own an 18.5 ft Stingray; I like the boat but the engine is far noisier than my old Sea Ray. I will explore using the same solution. Do I remove the current spray-on sound coating or coat over it? Would a more quiet muffler also help?

 

[lilmandavis]

Re: Noisy operating noise

is it a thru transom exaust? just make sure the foam is smooth- then apply adhesive a little thick and allow to become tacky. the put some pressure on it. make sure you put firm pressure on it cause thats what sets that stuff. make sure that all cracks are sealed. put some weather stripping on the hatch edges to futher reduce the noise. i would test a spot with the adhesive before id apply it to the whole surface! are the motor mounts in good shape? noise comes from vibration also.

 

[lilmandavis]

Re: Noisy operating noise

heavy threaded stainless screws would hold if thats a dense foam too!? that would help

 

[sail&power]

Re: Noisy operating noise

Glasply. Good input. I have some insulation coming. <br />Two questions: Which 3M adhesive did you use; you said to be careful. What do you estimate the sound reduction? 25%? 50%? More? To be safe, I plan on using the 3M adhesive and the metal hangers that are glued to the interior of the engine cover.