On March 5, 1995, approximately 1130 hours Pacific standard time (pst), a Piper PA-22-150, N4778A, registered to and being flown by a certificated private pilot, was substantially damaged when the nose gear collapsed during landing rollout following a partial loss of power while in cruise. The accident occurred near Forks, Washington, and the pilot sustained minor injuries. Visual meteorological conditions existed and no flight plan had been filed. The flight, which was personal, was to have been operated under 14CFR91, and originated from Forks approximately 1100. The pilot reported that at 1500 feet MSL the engine popped several times and began losing power. Unable to maintain altitude, the pilot executed a forced landing to a sand bar in the Hoh River, during which the nose landing gear impacted a large rock and separated. The pilot, whose last medical was issued September 4, 1991, reported to the FAA that the aircraft had not had an annual inspection for several years and that he was utilizing auto gas at the time of the accident. Inspection of the aircraft by FAA inspectors revealed multiple mechanical discrepancies and maintenance deficiencies, however nothing obvious was found that could cause the loss of power described by the pilot. The carburetor heat control was in the on position.