A cover arrangement of a hand-held power tool has a cover having at least one fastening element for connecting the cover to an additional component of the power tool. No water wash or caustic treatment is required. The drive device may be applied to, but is not limited to, a walk-behind vehicle that may include a snow thrower or blower. In an exemplary embodiment, an opening unit rotates the dust separator by a predetermined angle when the dust separator and the dust receptacle are unlocked. The water pump control system and method provide protection of the pump impeller during dry pump operation, such as when a watercraft engine is started while the watercraft is out of water, by turning off the clutch-controlled pump when no water is detected at the inlet of the water pump. The systems and related methods according to another aspect incorporate ketone tags andor trigger points to improve accuracy of results and to advance user compliance.