At approximately 1420 Mountain time, the airplane sustained substantial damage following a total loss of engine power and uncontrolled descent. The Private pilot, the airplanes sole occupant, sustained serious injuries. Visual conditions prevailed. An interview with the pilot revealed that the airplane had just undergone its most recent inspection and engine overhaul. The pilot reported that following the takeoff, and in a left turn to return to the airport he experienced a yoke control problem, followed by the aircraft impacting terrain north of the airport boundary. Examination of the wreckage revealed that the airplanes fuel selector was positioned in the vertical position, between the left and right positions.