On September 6, 1997, at 0930 hours Pacific daylight time, an experimental (amateur built) Hallam Stan RV-6, N93SJ, impacted terrain in an orange grove during an emergency, off airport, landing following a loss of engine power in cruise flight. The accident occurred 3 miles west of the departure airport at Woodlake, California. The aircraft was destroyed, the private pilot received minor injuries, and the second pilot was seriously injured. Visual meteorological conditions prevailed for the personal flight. The flight was destined for Selma, California, to purchase fuel. The first pilot was interviewed by a Deputy from the Tulare County Sheriff's Office about 20 minutes after the accident. The pilot said that after takeoff from Woodlake, he switched fuel tanks and then the engine stopped. He said that at departure, one fuel tank was 1/2 full and the other was 1/4 full, which should have been sufficient fuel to reach their destination. An inspector from the Fresno Flight Standards District Office examined the aircraft about 4 hours after the accident. He found no fuel in the left tank of the aircraft, only minimal fuel in the right tank, and no evidence of tank rupture or smell of fuel on the ground. The fuel selector was in the left tank position. The salvage agency, which recovered the aircraft the day following the accident, reported that "there did not appear to be any fuel in the left fuel tank and only a very small amount drained from the right tank. . ." They also reported that "both fuel drains appeared to be intact and there was not any evidence of fuel stain or smell at the accident site. . ." and that "when the fuel line from the firewall mounted fuel pump to the engine driven fuel pump was disconnected approximately one tablespoon of fuel was evident." When interviewed by the inspector the day following the accident, the first pilot said that they had taken off with the fuel selector on the left tank, and the left fuel gauge read half-way between 1/4 and empty. Each of the aircraft's two fuel tanks has an 18 gallon capacity. When interviewed a second time on September 12, 1997, the first pilot told the inspector that he had fueled the aircraft the day before the accident at Madera, California, by adding 5.7 gallons to each tank, which brought each tank up to about 1/2 full. The distance from Madera to Woodlake is approximately 60 nautical miles. He did not report how long he had flown after fueling. When interviewed by the inspector 2 days after the accident, the second pilot said that when the engine "started to quit" he turned on the fuel boost pump and switched the fuel selector to the right tank. When power did not resume he returned the selector to the left tank and prepared for the off-airport landing. The first pilot told the Safety Board investigator that he had recently purchased the airplane from the second pilot who was also its builder. He said he was "certain" there was fuel in the aircraft and thought that the engine failure was due to either a blocked fuel vent or a vapor lock in the fuel supply. In his report, the pilot reported departing from Woodlake with 21 gallons of fuel aboard. At 0954, the temperature at Visalia, 12 miles southwest of the accident site, was 79 degrees and the dew point was 54 degrees. A carburetor icing chart shows these conditions conducive to moderate carburetor icing at cruise power and severe icing at glide power.