Page last updated July 17, 2008



SOUND DAMPENING / making engine quite

If you find that the sound dampening material has worn down or deteriorated due to time, there are other options available. I have searched on the net for various options. I have attempted to order OEM replacement blankets, but I have been told that they are no longer made.


I have found some replacement material that is resistant to fuel and oils (I know because I have fuel all over it everytime I go out). It is cheap and its main purpose is to dampen sound waves. It is a closed cell neoprene material. Check it out, the most expensive part is the shipping at no more than $10.00. The material is $2.00 a square foot. Of course these engines don't need much, but order a little extra. 6 square feet should suffice but may be pushing it. 7 feet should be great with a little extra left over. If you want add additional layers, you will obvoisly need more. Keep in mind, it cannot be completely sealed; the carburetor needs to get air and heat needs to have an escape route.

edeadIt bonds really well to the plastic. It was a great improvement over having nothing. I may even mount some inside the middle unit (where exhaust tube is), that seems to be where the remaining noise comes from, but I have to remove powerhead again. I will eventually do that this winter to rebuild the cylinders and place new gasket on air intake (leaks fuel but I need to remove flywheel to get to them), and also give this thing a fresh, proper paint job.

It is called eDead 4. Make sure you get the eDead version 4, there are version 1, 2, etc but it is not foam, the other versions are a rubber butyl composite material better suited for sound dampening on vehicles. I have also used pieces of that on the engine covers. It works well, but is not as thick as the version 4. The rubber butyl seems as if it will melt at higher temperatures.

Granted, it is not completely noise free, but better and bearable. At 3000 RPMs, it is OK. Any higher than that, and it is loud.


If the links should fail, click on this link and from the left menu, select the Sound Deadening link and then choose eDead v4 - TekLite.

Another interst of mine would be to try to fashion a muffler for the exhaust tube and one for the opening that is directly behind engine. I have noticed this area is directly fed by the exhaust manifold and is probably the loudest area of the motor. Ffortunately, its directly behind the boat, but can still be heard during higher RPMs.

I was thinking of a simple device fashioned out of aluminum and placed within the chamber where the exhaust feeds into, prior to entering the exhaust tube.

It would require that I tear powerhead apart, but I plan to anyway when I repaint entire powerhead and rebuild cylinders next winter.

Another option would be to fashion a rig that attaches to the exhaust chamber at the rear of the engine. A simple metal screw should do the trick and it will be used to secure a simple muffler, changing the direction of the soundwaves and changing frequencies. I will try to construct a device that is small enough so that it will not be noticed.

That will have to wait a few weeks, though.



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