A walk-behind power unit is configured to detachably mount a variety of work implements to perform a corresponding variety of operations from a single power unit. The power unit includes an implement mounting mechanism that is pivotable about a generally vertical pivot axis corresponding to the power output shaft of the engine on the power unit. An attached work implement can be moved laterally to change the operating characteristics through pivoting the implement to either side of a normal direction of travel. An landscape edger implement can be mounted so that the width of cut of the cutting disk is varied as the edger implement is pivoted. A mower implement can be attached so that the cutting path of the mower blade is offset laterally as the implement is pivoted, thus permitting the mower to mow around obstacles offset to the side of the direction of travel.