On June 28, 2003, at 2015 central daylight time, an unregistered Quicksilver MXL II, collided with the terrain during a forced landing following a loss of engine power near Marceline, Missouri. The pilot was seriously injured and the passenger received minor injuries. The airplane was substantially damaged. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The pilot stated that his passenger had purchased the Quicksilver. He stated the owner contacted him so he could show the new owner how to operate the aircraft. The pilot stated that prior to the flight, he observed the owner add two gallons of fuel to the gas tank. He stated this brought the fuel level to three quarters of a tank. The pilot stated he departed the private airstrip alone and flew to a nearby airport where he made three full stop takeoffs and landings. The aircraft owner met him at the airport where he got on board the aircraft, sitting in the right seat. He stated they flew the aircraft for 5 to 10 minutes and they were getting ready to return to the airport when the engine lost power. The pilot reported, "I moved the throttle lever in a pumping motion and we did get fuel, but only at intermittent intervals." The pilot reported the aircraft contacted the ground as he attempted to turn in order to avoid trees. The local sheriff reported the fuel tank was clear and he was unable to see any fuel in the tank. The sheriff also reported the passenger stated to him that he felt they ran out of fuel during the flight.