A riding mower (10) includes a frame (12) adapted to support a passenger and a cutting unit connected to the frame (12) and having at least one rotatably-mounted blade (44,46,48). Interchangeable power unit support devices (64,124,126) each support either a battery unit (120) or an engine (66) connected to a generator (68). Each power unit support device (64,124,126) is releasably connected to the frame (12). A first electric motor (38,40,42) is provided to rotate the blade (44,46,48), and a second (77) to propel the mower (10). An output voltage generated by either the generator (68) or the battery unit (120) energizes the first and second electric motors (38,40,42,77).
