An apparatus for controllably positioning a work implement of an earth moving machine is disclosed. The work implement includes a boom and an attachment being attached thereto where the boom is actuated by a hydraulic lift cylinder and the attachment is actuated by a hydraulic tilt cylinder. Implement position sensors sense the elevational position of the boom and the pivotal position of the attachment and responsively produce respective implement position signals. A controller that receives the implement position signals, compares the relative position of the boom and the attachment with a pre-determined boundary condition, and produces an electrical valve signal. A valve assembly receives the electrical valve signal and controllably provides hydraulic fluid flow to the respective hydraulic cylinders in response to a magnitude of the electrical valve signal.