About 10 min after takeoff, the acft was damaged during a forced landing after the eng began sputtering & then lost power. The plt reported that he made a normal takeoff with the cowl flaps open & the mixture rich. After climbing about 1100 ft (to 3500 ft MSL), he closed the cowl flaps & leaned the mixture slightly. About 2 to 3 min later, the eng began sputtering. The plt observed the oil temp rising. He said he opened the cowl flaps, turned on the carb heat, changed the fuel sel & checked the magnetos. The eng lost all power & the plt attempted to land on a road. However, he maneuvered to avoid power lines then elected to land in a field. During the apch to land, the acft hit a fence & was damaged. A lack of fuel was noted in the fuel line leading to the carburetor. The acft had been refueled with 37 gal of unleaded automotive fuel. The air temp was reported as 85 deg. No pre-accident problem was found that would have caused a loss of power, vapor lock or other eng/fuel sys problem. The wobble pump was not used while attempting to restore pwr.