On May 31, 2001, about 1645 Pacific daylight time, a Luscombe 8F, N1389B, was substantially damaged during an off airport forced landing following a sudden loss of engine power approximately 2 1/2 miles south of McNary Field, Salem, Oregon. The airplane is owned by the second pilot, and was being operated as a visual flight rules (VFR) instructional flight under the provisions of Title 14, CFR Part 91, when the accident occurred. The first pilot, a commercial pilot/certified flight instructor, and the second pilot, a private pilot receiving instruction, were not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight. The flight originated from a grass strip near Salem, Oregon, approximately 15 minutes prior to the accident. The pilot's planned destination was McNary Field. At the time of the engine failure, the second pilot was manipulating the controls of the airplane. Shortly after the engine failure, the first pilot assumed control of the airplane and initiated the off-airport landing. According to the first pilot, the airplane was in a level cruise flight configuration approximately 1,300 - 1,400 feet mean sea level (MSL) when the engine suddenly lost power. After confirming the engine failure, the first pilot initiated an off-airport forced landing to an open field near Salem. He stated that he intentionally stalled the airplane just before touchdown in an effort to prevent the airplane from "... flipping on it's back in the tall grass." When the airplane touched down, the main landing gear collapsed. On June 4, 2001, the aircraft wreckage was recovered by H.L.M. Air Services, Inc, and transferred to their storage facility in Independence, Oregon. On July 2, a representative from the Portland, Oregon, Flight Standards District Office examined the wreckage and reported that there was no evidence found to indicate a mechanical malfunction or failure of the airframe, engine or associated components. At the conclusion of the inspection, the airplane's carburetor was shipped to the manufacture for further examination and testing. On June 21, 2001, representatives from Precision Aviation Products Corporation and the NTSB examined the airplane's carburetor. Flow bench testing and disassembly of the carburetor revealed no abnormalities with the carburetor. At the conclusion of the investigation, the aircraft wreckage was released to PAC Northwest, Redmond, Washington.