Yeah, OT, but I had exactly the same problem. 5K generator with a vintage
cast iron 9hp B&S engine. So loud it made my teeth rattle. I also happen
to have a vintage Cub Cadet tractor with a 7 hp Kohler engine that runs very
quiet. The Kohler has a large, 6 inch diameter muffler about 12 inches long
with a 1" "tailpipe". I pulled the muffler off the Kohler and put it on the
Briggs. The generator runs much quieter now, although not as quiet as I
would like, but not bad for an engine spinning at 3600rpm under load. I
bought a replacement muffler for the Cub. Total cost was $25.

Bob

"Bob S." wrote in message
...
Well, it's Black Friday and I'm not going anywhere near a mall this
weekend
! Got a small job I've been meaning to around to so off to the borg to
pick
up some materials.

I have a 5000W emergency power generator I got a year ago that has been
very
handy in here in the northeast. But like most, the damn thing is loud and
you can't hear yourself think if you're within 25 feet of it. Decided
it's
time to tame the beast a bit so I picked up a 2' section of 6" duct pipe,
two 6" to 4" reducers, a roll of 1/4" sq hardware cloth and a small roll
of
unfaced fiberglass insulation (pink stuff).

I saw it someplace that I can't find now but the idea is to make a
glass-pack muffler. I'll make a 4" tube with the hardware cloth, wrap a
layer of the insulation around that and then stuff the whole works in the
6"
pipe. Put the reducers on each end and hopefully it will cut down the
noise
level.

Plan on just setting this muffler near the muffler that's on the B&S 10hp
engine so that exhaust feeds directly into the secondary muffler. Since
it's essentially like the glass-packs we used to put on the old flatheads
(remember those guy's and gal's?) there is no back pressure due to baffles
and the insulation absorbs the noise.

I did take a look for sites that could help me figure out how to make a
baffle type muffler (noise canceling) but nada, so the glass pack seemed
the
best way to go rather than chance burning up a engine experimenting.

Anyone know of a better method? This generator gets wheeled out to the
edge
of the garage when needed, so whatever I do, needs to be portable. B&S
suggests making a baffle chamber using ply and 2" think foam insulation.
That would seem kinda bulky to me compared to a 2'x6" piece of duct.
Besides, I'll be the only guy on the block with a glass pack on his
genny......

Bob S.