An engine muffler and spark arrestor includes an outer tube extending along
an axis and having an inlet end and an outlet end. A plurality of
substantially identical nested discs are disposed coaxially adjacent the
outlet end of the outer tube. Each of the discs has a centrally located
aperture. Each of the discs also has at least one slot extending
therethrough. An end cap is disposed on a distal end of the set of discs.
The end cap has a solid central portion which forces at least a portion of
an exhaust gas flowing from an internal combustion to which the muffler is
connected to flow radially outwardly along interstitial spaces defined
between each pair of discs and then flow axially in a direction
approximately parallel to a longitudinal axis of the muffler.