Quiet muffler for lawn tractor

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?
David
Reply to
David R. Birch
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Quite likely, the noise that you hear comes mainly NOT from the exhaust. It is the mechanical clattering of various parts.
Reply to
Ignoramus12247
You can reduce the noise with a better muffler, but keep in mind it fires every cycle. I KNOW its not a 2 stroke BUT it does fire on every stroke. the motor fires both on compression and exhaust, and it fires at some point before TDC so the exhaust valve is just about shut when it fires.
Reply to
Waynemak
Blink. Blink. Fires?
I don't think so. It may provide spark on every cycle, but it has nothing to burn for it to "fire". It's discharging the spent air/fuel mixture that fired on the previous cycle. I certainly can't imagine the spark creating that kind of noise. Unless something is woefully wrong with the engine, the gasses contained within the cylinder on the exhaust stroke won't ignite.
Air cooled engines tend to be noisier than water cooled engines. I imagine the engine in question is air cooled. Years ago I converted an 8 horse air cooled Kohler engine to a water cooled engine. It ran much quieter. The water jacket provides considerable damping.
Harold
Reply to
Harold and Susan Vordos
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
Reply to
Jon Elson
I'm curious how you did this. Weld up a water jacket around the cylinder?
Lane
Reply to
Lane
hey, i was very proud of a "muffler" i made for my 7 hp kohler troy-bilt roto tiller. what a crappy muffler it used to have, rusted out in no time, replaced it and rusted out again, quickly. it then became just a short empty tin can with louver slots cut in it. finally got SICK of the NOISE and having the exhaust fumes blowing directly in my FACE when i was tilling. cut a mounting flange out of 1/2" steel plate (the oblong thing with the big hole for the exhaust and two 1/4" holes on both sides for bolts to go through) and carefully prepared a expended (hand held style) propane tank (threw it into a huge bon-fire) (and quickly walked far away). welded an elbow from the flange to the propane tank, then another elbow to a 9 inch long extension to route the exhaust down and forward below the wheels and out toward the front. terminated the exhaust pipe with multiple 1/2" holes through the side of the pipe in an attempt to "break up" the exhaust gases and noise and direct the fumes forward instead of straight down into the dirt. the propane tank has no baffles inside, and i don't think it needs any but prolly would (with further effort) be even quieter with baffles. it made the tiller go from NOISY to darn near quiet. i was concerned it might affect the performance of the engine or harm it in some way but i think any reduction in performance is negligible. a lot of work though. for me it was worth it. i'm still pleased with that muffler every time i use the tiller. looks cool too.
b.w.
Reply to
William Wixon
No. The cylinder was mounted on a rotary table so the fins could be either reduced or eliminated, using a stub arbor and a side cutter, then a stainless band was fabricated that was held by a pair of stainless hose clamps. The top and bottom fins were left almost full size in order to create the water area between them. The fins didn't go all around, so the jacket terminated with pressure pads. It worked like a charm. Made a new head from aluminum, and a water pump. This went into a boat that didn't have room for a commercial power plant. It drove an 80 amp alternator and worked flawlessly as long as we had the boat, which had an electric refrigerator, the reason for the needed additional charging capacity. I have pics if you're interested. Let me know and I'll forward them to you.
Harold
Reply to
Harold and Susan Vordos
"William Wixon" wrote in news:3xTne.68$ snipped-for-privacy@news01.roc.ny:
That sounds like a fun project. As a simpler solution I've started wearing a pair of cheap earmuffs whenever I run something loud. It is so nice to finish cutting the grass and not have ringing ears.
Reply to
Dave
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
J>
Reply to
Rex B
I wouldn't mind seeing a picture or two of that Harold.
The the OP, I got a box of earplugs and I dig a pair out when it's time to run the lawn equipment.
It might be that you've got too big of a muffler on it- can't get enough backpressure to really break up the impulses..
John
Reply to
JohnM
I bought two of these SuperTrapp "Quiet" mufflers... and have been VERY happy with them (one is on a 12hp Kohler powered Miller welder).
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David
Reply to
David Courtney
A neighbor had me help with the small amount of welding needed to adapt a Honda generator muffler to fit his B&S powered generator. All that was needed was to fabricate the elbow to mate the different style flanges and to fill the 6 or 8 holes in the muffler case that I presume were for some bracketry on a Honda generator.
I didn't hear the results, but the owner was happy with the improvement. The generator was used for camping at shows and swap meets where quiet makes for good neighbors.
Reply to
Mark J
I have a Supertrap from a motorcycle that I've avoiding throwing away. Maybe I'll adapt it to the Cub Cadet.
- - Rex Burkheimer WM Automotive Fort Worth TX
David Courtney wrote:
Reply to
Rex B
I'm curious how you did this. Weld up a water jacket around the cylinder?
Very interesting, thanks. Another thing comes to mind with this kind of conversion. I know that engines are engineered to operate at certain temperatures for efficiency. Wouldn't a conversion as you describe have changed the operating temperature to such a drastic degree to upset that efficiency? Or isn't that the case with air cooled engines?
Lane
Reply to
Lane
Ringing ears you say?! I have those all the time thanks to my working at Boeing on the 767 wing line. And yes I was wearing ear protection, two actually; foam ear plugs and headset. The noise was so loud when we were riveting wing panels that you could feel your chest vibrate. That wing panel acted like a huge drum skin.
Lane
Reply to
Lane
I noticed that the mowers that commercial landscape service guys use around office buildings are quieter than the same mufflers used on homeowner mowers. Now why they can't put those mufflers on the homeowner mowers?
Lane
Reply to
Lane
When I was young I think the after effect was more like a hissing, but as I have gotten older it has gotten more like a ringing. If I'm not careful and do something especially loud they will sometimes ring for several days. My Dad did aircraft work and ended up quite deaf.
Reply to
Dave
In my opinion, for what it's worth, yes, the operating efficiency is and was altered, likely not anywhere nearly as good as it may have been, but I had no alternative. It was important to get a functioning generator because we had two dead batteries almost constantly. While it was likely harder on fuel running slightly cooler, imagine what it was costing us to run around Lake Powell for hours just to charge our batteries. We'd go through 80 gallons of fuel in a day. From all indications, we could run the power plant for hours on just a couple gallons of gasoline. A much better deal, and we didn't have to have the boat in motion to do so. At night, when we sat around a big fire, sipping scotch and listening to music, I'd run it to get the batteries fully charged for the night. By then, I had installed yet another battery, so we had three. The third was isolated from the other two and used for only light duty, assuring we had power to start the generator should the other batteries puke.
One of the things I did was to go to a hotter plug, so it wouldn't foul prematurely. I'm not convinced even that was necessary. As I said, we had absolutely no problems with the unit, which we used for several years. It was still functioning flawlessly when we sold the boat back in '90.
I had tried an earlier version of the power plant, using an air cooled engine. Even with a second blower running, the engine compartment got way too hot. By going to the water cooled engine, including a water cooled exhaust system, that was no longer a problem. I ran the second blower alone afterwards, and it kept the engine compartment at an acceptable temperature.
Harold
Reply to
Harold and Susan Vordos
Because they cost anywhere from $150 to $300. Some are even more. Same thing holds true for generators- the mufflers can get quite expensive.
-Carl
Reply to
Carl Byrns

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