On October 9, 2002, at 1730 central daylight time, an amateur built Madewell EAA-Biplane-P, N21WL, sustained substantial damage during a forced landing to a swamp after a loss of engine power. The private pilot was not injured. The Title 14 CFR Part 91 flight departed Forest Lake Airport (25D), Forest Lake, Minnesota, at 1705 on a local flight. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported he had been practicing power on and power off stalls north of the airport. He returned to 25D and flew over the airport at 2,500 feet msl (1,575 feet agl) to check for two aircraft that were in the traffic pattern. He reported that when he was southwest of the approach end of runway 13 (2,650 feet by 150 feet, turf), he lost power to the engine and immediately turned right to land on runway 13. The pilot reported that he could not make the runway and executed a forced landing to a swamp. The pilot reported that he had switched the fuel selector from the 9 gallon fuel tank to the 12 gallon fuel tank about 7 miles prior to the loss of engine power. The pilot reported that during his preflight inspection, he did not sump the tanks individually for contamination, but he did sump the fuel scupper drain once to check for contamination. He reported that he had drained and fueled the 12 gallon tank with about 6 gallons of 100 LL Avgas twice about 2 weeks earlier when he purchased the airplane. He reported he had topped off the 12 gallon tank with 100 LL Avgas about two times since purchasing the airplane. A Federal Aviation Administration Airworthiness Inspector conducted a post-accident examination of the airplane. He reported the engine exhibited continuity and thumb compression. He reported, "The fuel line was wrapped with foam and aluminum speed tape to prevent vapor lock." The inspection of the airframe and engine revealed no pre-impact anomalies.