Abstract: Self-propelled walk-behind lawn mower having a rear discharge chute. The rear wheels of the lawn mower are driven by the engine through an axle which is fixed relative to the outer housing and which extends below the discharge chute so as to not interfere with the flow of grass clippings from the discharge chute. A transmission is provided for driving the rear wheels and is offset to one side of the discharge chute so as to be clear of the path of discharged grass. All four wheels of the mower are simultaneously adjustable and the driven rear wheels are adjustably by pivotal movement of a driving transmission that interconnects the wheels with the driven axle. In addition, a combing arrangement is provided on the outer housing for combing grass upwardly before it reaches the cutting blade.