WOT too loud. Can I quiet it any?

mays

Cadet
Joined
May 16, 2005
Messages
17
I have an old 15hp outboard. It runs good, but at full throttle it runs so loud that it starts to hurt my ears after a while. I tried putting sound dampening material used in vehicle sound systems on the inside of the cowling and this helped a bit, but I would like to know if there is any way to do more.
 

CATransplant

Admiral
Joined
Feb 26, 2005
Messages
6,319
Re: WOT too loud. Can I quiet it any?

What brand of outboard are you using, and what model? That could make all the difference in the answer.
 

mays

Cadet
Joined
May 16, 2005
Messages
17
Re: WOT too loud. Can I quiet it any?

It is a 15 hp 1990 Force sold by Sears as Gamefisher. Not the greatest motor, I know, but I was fishing out of a kayak before that and the price was right. It has an exhaust port under the cavitation plate, not through the hub. I have thought that maybe at the higher speeds the exhaust is getting free to the air and I am hearing this. I tend to think that it is mostly induction noise or a combination.
 

CATransplant

Admiral
Joined
Feb 26, 2005
Messages
6,319
Re: WOT too loud. Can I quiet it any?

Hmmm....if the exhaust port is well underwater, that shouldn't cause all that much noise, even at WOT. But...it is under water adequately? I'm assuming this is a short-shaft engine, since I haven't seen any long-shaft Gamefishers. How high is the transom on your boat? More than 15"? If so, I suppose you could be generating enough turbulence to open the exhaust port to the air. Now that would be loud. In that case, getting the motor lower in the water should help. Does the noise sound like it's coming from the water?<br /><br />Induction noise, on the other hand, can be pretty loud on a two-stroke motor. Does the noise sound like it's coming from the powerhead area? How much louder is it if you run the engine with the cowling off?<br /><br />Another possibility is the gasket where the powerhead connects to the mid-section of the motor. On some motors, like the 60's Johnson 9.5 hp models, this was a common problem, and there are similarities in design between those and your Force.<br /><br />Figure out where the noise is originating, and there's probably a solution.
 

Mark42

Fleet Admiral
Joined
Oct 8, 2003
Messages
9,334
Re: WOT too loud. Can I quiet it any?

Is the carb missing the sound baffle box?
 

bossee

Senior Chief Petty Officer
Joined
Jul 18, 2002
Messages
727
Re: WOT too loud. Can I quiet it any?

Hi,<br />It is also amazing how much noice an unbalansed prop can produce - via transom and to other parts of the hull/boat. I once had a 65 hp Suzuki 2-stroke and the prop was out of balanced. I bought a new (and had the old as spare), the outboard was much quiter after that. Just a suggestion. Good luck.
 

mays

Cadet
Joined
May 16, 2005
Messages
17
Re: WOT too loud. Can I quiet it any?

I am not sure what the carb baffle box is. Would that be something that I can see with the cowling off?
 

ED21

Master Chief Petty Officer
Joined
Aug 26, 2003
Messages
829
Re: WOT too loud. Can I quiet it any?

If nothing else get some cheap earplugs for running WOT. <br />I'm guessing your ears hurting means you're over the threshold for eventual hearing damage.
 

willamettejeff

Chief Petty Officer
Joined
Nov 15, 2004
Messages
550
Re: WOT too loud. Can I quiet it any?

The baffle box would be attached to and covers the front of the carb or carbs.
 

BoatBuoy

Rear Admiral
Joined
May 29, 2004
Messages
4,856
Re: WOT too loud. Can I quiet it any?

If it's an aluminum boat, you might want to get one of those rubber transom pads to eliminate any resonance.
 

Marauderk

Petty Officer 2nd Class
Joined
May 7, 2005
Messages
168
Re: WOT too loud. Can I quiet it any?

My 50 is very loud at WOT and i have tried just about everything i can think of and it has not helped but i used some rubber mounts and it seems to be a litle bit better.
 
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