The flight instructor was conducting a local instructional flight with a new student pilot. Following the preflight inspection and engine start, the flight instructor noted that the fuel selector looked to be positioned “in the right place,” and that neither he nor the student touched the fuel selector for the entirety of the accident flight. They subsequently conducted about 15 to 20 minutes of the instructional lesson on the ground, while the engine was running. During engine run-up, the flight instructor noted that “the fuel pressure indicator went to zero” so he turned on the airplane’s electric fuel pump and the fuel pressure recovered. After 1 to 2 minutes, the flight instructor turned off the electric fuel pump and the fuel pressure returned to the normal range and remained there. After takeoff, and during the initial climb, the engine started to “lose and gain power,” so the flight instructor attempted a turn back to the departure runway. Halfway through the turn, the airplane lost all engine power, and the flight instructor landed the airplane in a grassy area, but encountered uneven terrain. The airplane sustained substantial damage to the left wing during the landing. Initial postaccident examination of the airplane revealed that the fuel selector was of a configuration that the handle of the rotary valve faced away from the fuel tank being selected, while the opposite side of the handle indicated the selected tank or shutoff position. The operator had painted a gray/white stripe on the handle and fuel selector valve placard that showed the selected tank to aid pilots in correctly selecting the desired position. Following the accident, the flight instructor stated that he was confused by the white paint stripe on the fuel selector. He also stated that the airplane’s owner advised him after the accident that the fuel selector had been found in the “off” position after the accident. The wreckage was subsequently disposed of by the owner, and no additional detailed examination was conducted to determine if the fuel selector valve handle, the valve mechanism itself, or fuel selector valve placard were correctly oriented and that the internal valve mechanism was intact, nor were the engine or fuel system otherwise examined or tested. Based on this information, the reason for the loss of engine power could not be determined.