Quiet That B&S

[Unregistered]

I have a 6hp B&S powered generator. I would like it to be quieter. I am advised not to do any modifications to the muffler because that might reduce power and affect the generator output. Is there no way to quiet this thing down? Couldn't you put a big ol' car muffler on it without creating a lot of backpressure. I don't care what it looks like.
Thanks,
Bill

[Mr T]

Is this generator moved around alot or does it stay in one spot?

What kind of surface is it sitting on? (dirt/grass, concrete, wood?) Concrete will bounce sound back, a wood structure can act as a resonating chamber similar to a guitar and make the sound louder. If the generator is not on a solid, smooth surface it may rattle and vibrate, creating additional noise.

Is it near any walls/buildings? This too can cause resonations.

What condition is the current muffler in? Could it be damaged or rusted out causing a bypass? Does the muffler look like the origional one? Any chance of someone changing or replacing it with the wrong one?

Is the muffler aimed at the ground or a hard surface (wall, ect) (and within a foot of it)

A 6hp engine is not that loud. It is what is on many larger push lawnmowers. It soulnds It sounds as if you have something that is amplifying, bouncing or resonating the sound. Its best to start with that issue before making any mods.

[Unregistered]

Its new. We got it for emergency power to run a small AC, small refer, and one or two lights if we loose power during and/or after a hurricane. I understand all about the external factors you mention. We will try to find the quietest place for it we can and leave it there. But it is still irritatingly loud after a few hours of running; particularly when you are trying to sleep. I don't like irritating the neighbors either. A neighbor several doors down had one going last year during the night that was too loud (I know - now that we have one we won't hear his). It doesn't seem like it should be that difficult to quiet one down. I know as an air cooled engine, it won't be as quiet as a water cooled one but the exhaust noise should be fixable.

[Mr T]

I'd still like to know the answers to my above questions (other then the 'is it new' one). You will be suprised how the smallest, unexpected change in the placement will affect the sound level. I may have some other ideas too depending on your setup.

Is this only for if (when as they are predicting...) you get hit? Gonna keep it on standby for storms too?

What area of Florida (?) are you in?

[Unregistered]

Last question first: We are in Mobile, AL
It will be on standby (in storage) until needed for any power outage. This is usually as a result of very severe conditions like hurricanes.
I will most likely place it near the house, in the open, on grass, with exhaust pointing away from the house. Exhaust comes out on the side of the unit. If it is raining, I will probably put it under cover of the porch; concrete floor, wood roof, wood siding on house.
I could also put it on the other side of the house under a wood deck where it would sit on leaf litter and dirt. This might even muffle the sound some as the deck (about 3' off the ground) has wood slats closing up the underside. The deck floor is 2x6s with 1/4" spacing.
I haven't needed to use it yet (although I have test run it) and haven't had a chance to experiment with different locations. Locations will be somewhat limited by the length of cables I get. I hope to keep their length to about 50 feet.
Hope this helps,
Bill

[Mr T]

I would find a BS dealer or shop (but not a dealer full of BS) and talk to them before making any major changes to your engine.

If you put it under your deck you can experiment with baffles. Make sure you keep enough air flow around the unit so you dont starve it or trap in heat. Any open cell type foam, fuzz board ect will absorb sound very well. Cover the exterior with something weather resistant. Wood is hit and miss with sound, sometimes it will bounce off it, other times it may absorb the sound. I think the deck itself will be a problem if there is nothing between the deck and the generator.

Loose dirt will absorb sound, compacted dirt, and rock will not. I dont know what lavarock will do. I would think the sound would bounce around within the porous surface and it would absorb sound. A bag costs a few bucks... may be worth a experiment.

[Unregistered]

Yup. Already went to a local small engine shop. He is the one that advised against muffler mods. Not sure if he is just being careful to cover his backside (BS) or if the concern is real.
Thanks.

[Mr T]

Get a 2nd opinion from somewhere else to be safe.

If so, take their advice as your house is plugged into this thing. DOnt wanna screw it up.

I'd look into building a baffle/enclosure around it. Look around at other people's setups.. See what they have done. Just dont trap in heat or starve it from air.

I would suggest a 3 sided enclosure with a roof. Use fuzz board and other sound deadening materials.. Make sure there is plenty of room between the generator and the walls.. The last thing you want to do is start a fire. Aim the ennclosure away from other houses and stuff that will reflect sound. It will be quiet as long as your not inline with the opening.

[Unregistered]

What are you calling fuzz board?

[Mr T]

It is a brown fiber board sold in 4x8's, various thicknesses. Was very popular back in the 50's for wall sheething. It seems to be making a comeback. I would think that it would absorb sound fairly well. Same with the poly foam board once you remove the foil on the inside. Sound will get lost in a porous surface.

[Unregistered]

OK. It's what I used to know as insulation board. I've never seen in anything but 1/2". When available, it was painted white on one side. I can still get it at local home supply but it's coated with asphalt on one side.

[LostInTheDesert]

Unregistered: If you're going to build a box to quiet your generator, you might consider lining it with this stuff:

http://www.acousticalsolutions.com/products/foams/sonex.asp

It's used in recording studios, and probably won't take kindly to the severe environment it could face here; you might need to replace it from time to time.

Just a thought from a non-professional who is very sensitive to noise.

Dave