On December 8, 2000, at 1400 central standard time, a Larson Aero Comp-6, N4334Z, nosed over during a forced landing in a snow covered field near Brainerd, Minnesota. The forced landing was made as a result of a total loss of engine power. The private pilot was not injured and the airplane was substantially damaged. The 14 CFR Part 91 flight was operating in visual meteorological conditions without a flight plan. The purpose of the flight was to check the calibration on a newly installed fuel gauge sending unit. The flight originated from a Jackson Field, in Brainerd, Minnesota, at approximately 1320 central standard time. The pilot reported that he had recently replaced the fuel sensors and calibrated the fuel system with the tailwheel on the ground. In addition, he "stick measured" the amount of fuel in each tank. The airplane holds a total of 60 gallons of fuel. He reported that he departed on the flight with 26 gallons of fuel on board and that the fuel gauges were indicating just under half full. The pilot reported that approximately 30 minutes after departure he noticed the fuel gauges were reading low. He reported he was not alarmed as he thought they were erroneous and that he would need to recalibrate the fuel system with the tailwheel in a flight attitude. Approximately 10 minutes later, the engine began to lose power. The pilot chose a hay field in which to make a forced landing. He reported that the main gear were on the ground; however, he was unable to keep the tailwheel down due to the snow. The airplane subsequently nosed over. The pilot removed the airplane from the accident site prior to notifying either the NTSB or the FAA of the accident. He reported that his examination of the airplane revealed the fuel siphoned over board due to a loose fuel cap.