On February 11, 1994, at 1740 Pacific standard time, a Grumman AA-1A, N9614U, lost engine power while in cruise and nosed over in soft soil near Bishop, California, during a forced landing in a field. The aircraft was owned and operated by the pilot. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation. The aircraft incurred substantial damage. The certificated private pilot and his one passenger were not injured. The flight originated at Santa Monica, California, on the day of the mishap at 1455 as a cross- country personal flight to Mammoth Lakes, California. In his written report, the pilot stated that he departed with full fuel, and on the left fuel tank. At 1610 hours, the pilot switched to the right fuel tank when the gauge for the left indicated approximately one-quarter. The pilot overflew Bishop at about 1720 hours climbing from an en route cruise altitude of 7,500 feet to 9,500 feet for mountainous terrain. Shortly thereafter, the pilot switched back to the left fuel tank and the engine quit. The pilot said he immediately turned on the electric boost pump and switched back to the right tank; the engine ran for a few minutes, then quit again. The pilot was unable to obtain an engine restart thereafter. The pilot reported that at the time the engine problem began, he turned around and headed for the Bishop airport, which was at an estimated distance of 12 miles. The aircraft had insufficient altitude to reach the airport and the pilot landed in a field. The aircraft encountered soft soil and nosed over. The aircraft retrieval firm which recovered the aircraft reported that no fuel was found in the aircraft tanks. The soil beneath the aircraft was examined, with no odor of fuel evident. After recovery of the aircraft, the fuel system was examined by a mechanic at the wreckage storage facility. Both the engine driven and electric boost pumps were found to function normally. No obstructions were noted in either the fuel selector or system lines. No fuel was found in the fuel lines from the wing root to the fuel selector, and only residual fuel was noted in the fuel line from the selector valve to the electric boost pump.