On February 2, 2002, at 1300 Pacific standard time, a Robinette Ultra Pup, N2221X, landed off-airport following total a loss of engine power on climbout from Rio Vista Municipal Airport, Rio Vista, California. The private certificated pilot and pilot-rated passenger were not injured. The experimental, amateur-built airplane was substantially damaged. The local area personal flight was operated by the owner under 14 CFR Part 91. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that during the initial climb after a slow-flight, low pass down runway 25 (4,200feet long by 75 feet wide), while about 200 feet above ground level, the engine lost all power although the propeller continued to windmill. After the accident, there was about 9 gallons of 100-octane aviation fuel aboard. Earlier the same day he had flown from Concord, California, to Rio Vista on the same tank of fuel. The pilot suspected that carburetor icing was the cause of the engine loss of power. The airplane was equipped with a Mosler converted automotive engine, and was equipped with carburetor heat. The carburetor heat control was in the "on" position when engine power was lost. A generic carburetor icing probability chart used by the Safety Board showed the ambient temperature and dew point conditions to have been within the region marked "serious icing - cruise or climb power."