Locate the mower muffler by following the exhaust pipe from the front of the engine.
Determine the correct socket size for the two bolts holding the exhaust pipe to the engine. Unscrew the bolts and remove the pipe from the engine. Pull the pipe out of the muffler.
Inspect the muffler for cracks or fractures. Remove the muffler by unscrewing the mounting bolts. Replace the muffler if you find cracks or fractures.
Peel off the old gasket on the exhaust port of the engine. Scrape away debris from the port. Set the new gasket in place.
Mount the muffler onto the lawn mower using the mounting bolts. Slide the exhaust pipe back into the muffler. Mount the exhaust pipe back into the port at the engine. Tighten the pipe back into place.