Abstract: In a diesel for a hydraulic excavator or the like, the speed regulator of the injection pump is set by a lever which is pivoted by a piston-cylinder unit against the force of a return spring. Before or during operation under load, the piston-cylinder unit brings the setting lever to a preselected load position and, after terminating or interrupting operation under load, moves it to its idling position. At least one handle of the control levers for the hydraulically movable implements of the excavator is provided with a switch which, on first actuation, so operates a magnetic valve that the piston cylinder unit or the return spring moves the setting lever to the load position and, on being actuated again, returns the setting lever to the idling position.