I have just successfully made a homemade quiet muffler. It was fairly easy. All you need is an empty Acetone can, 6 inches of galvenized pipe that will screw into exhaust port. First punch a hole on the bottom of the can, slightly smaller than the pipe. Second, attach it to the pipe. Make sure the cap is off!!!! screw the pipe into the exhaust port. To attach the can and pipe together you can solder, cold weld ,or braze. I used Liquid Steel cold weld, it will work great. Do not weld. Make sure cap is off!! Finally, crank the engine. I used it on my 11Hp briggs engine that was made in 1979!