Abstract: An internal combustion engine is mounted so as to be vibration isolated. The engine supports a muffler and muffler heat shield assembly, the latter forming part of a combined engine and muffler compartment and being constructed such that the engine exhaust acts to pull ambient air into the compartment, about the muffler and out of an exhaust duct in the top of the heat shield assembly. The compartment also includes a noise baffle for preventing sound waves from travelling directly from the engine and muffler to openings provided for permitting ambient air to enter the compartment.