Abstract: An internal combustion engine assembly comprises an internal combustion engine and an exhaust assembly connected to an exhaust outlet of the engine. The exhaust assembly comprises: an exhaust pipe having an inlet end connected to the exhaust outlet of the engine and an outlet end; a generally cylindrical muffler having a central longitudinal axis, the muffler having an inlet end and an outlet end; and a muffler support having a pivot; the muffler having an operating position, in which operating position the said axis of the muffler is substantially vertical and the inlet end of the muffler is in gas flow communication with the outlet end of the exhaust pipe, and a storage position, in which the said axis of the muffler is substantially horizontal. The muffler is connected to and arcuately movable about the pivot of the muffler support between the operating position and the storage position.