David R. Birch wrote:
I have an old lawn tractor that I want to make quieter. It has a single
cylinder Briggs & Stratton 8hp engine that has a muffler that doesn't
muffle. I replaced that one with one for a 9-16hp B&S engine, but it
didn't get any quieter. These seem to do nothing except provide back
pressure.

Anyone have a design for a muffler that will make it possible to talk
with the engine running without shouting?
I had a left-over bullet-style muffler (not a glass-pack straight-thru,
but a real 3-chamber muffler) from another project, so I put it on my
16 Hp Wisconsin one-lung tractor engine. It definitely helps, but it
really doesn't reduce the total noise, just moves the sound spectrum.
It goes from an ear-splitting gunshot rat-tat-tat to a low bum-bum-bum,
that is a lot more tolerable. But, I'd like to reduce it more. Still,
it helps a lot. I managed to ram into something and broke the fitting
off last fall, so I got a reminder of how loud it was without the
muffler.

You don't need quite so big a muffler with your 8 hp engine, so you
might be able to find something for commercial lawn machines, or
other small engines that will do the job.

If you really want to go insane and BUILD one, you might need a TIG
welder or something like that. Look at a real muffler, like on a car.
They have three chambers, connected by perforated pipes. The gases
expand out of each pipe into the next chamber, then into a pipe to
the next chamber, etc.

Jon