My mower exhausts right our the front grille, pointing forward.
Yours probably does something similar. I think adding tubing to route
the exit into the grass would be very beneficial. Thickwall tubing would
be better than thin, though harder to work with. Support would be
critical, otherwise harmonics would make the noise worse, and it would
crack in short order.
Even better would be dumping it into the mower deck interior where
the exhaust pulses could be mixed into the maelstrom therein. But that
adds an extra level of complexity, allowing for deck adjustment. Still
if the deck moves perfectly vertical, you could make the exit vertical
so it slips through. If not vertical, you would have to match the angle
of movement. Usually there is an area in the periphery of the deck
where no blades reach.
Of course, I haven't done this

No charge for this consultation.


Rex Burkheimer


Jon Elson wrote:
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