On May 31, 2006, about 1530 eastern daylight time, a Weatherly 201B, N1281W, was substantially damaged during a forced landing, after it experienced a loss of engine power while maneuvering near Southampton, New Jersey. The certificated commercial pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan had been filed for the local aerial application flight that was conducted under 14 CFR Part 137. According to a Federal Aviation Administration (FAA) inspector, the pilot was conducting his third aerial application of the day, when the airplane experienced a loss of engine power. The pilot attempted a forced landing to a field; however, during the landing, the airplane impacted shrubs and came to rest in a marsh area. The airplane was manufactured in 1975, and equipped with a Pratt & Whitney R985-AN3 radial engine. Examination of the engine by an FAA inspector revealed that when the crankshaft was rotated by hand, thumb compression was attained on all cylinders; however, the supercharger did not rotate. The carburetor was dissembled and no preimpact discrepancies were noted.