A walk-behind power unit is configured to detachably mount a counter-rotating powered drum work implement on a centrally pivoted implement carrier. The pivoting of the implement carrier from a central position to either side causes the discharge of the powered drum to be located on a desired side of the work implement. The work implement can also be positioned to discharge forwardly from the powered drum member. A lift apparatus is provided to be cooperable with an associated set of support wheels to affect the positioning of the powered drum member between a lowered operative position and a raised transport position. The powered, counter-rotating drum member can be either a rotatable broom or a power rake. In the broom configuration, the lift apparatus can move the lid member, after first unlatching the lid member from the frame of the work implement, to fix the lid in an opened position.