On September 16, 1996, at 0727 eastern daylight time, a Beech BE-33, N108VW, collided with the ground during an emergency landing following a complete loss of engine power near West Palm Beach, Florida. The personal flight operated under the provisions of Title 14 CFR Part 91 with an instrument flight plan activated. Visual weather conditions prevailed at the time of the accident. The airplane was substantially damaged, and the pilot received serious injuries. The flight departed Fort Pierce, Florida, at 0700. According to the pilot's wife, he was changing the fuel selector from the left tank to the right tank when the engine lost power. The selector handle had reached the off position when the engine quit. The engine lost power, and the pilot attempted an emergency landing to the West Palm Beach North County Airport. The airplane collided with the ground one mile west of the airport. Examination of the fuel selector valve assembly disclosed that upper roll pin was not installed in the rotor assembly. A search of the wreckage at the accident site failed to recover the upper roll pin. An examination of the machined roll pin installation hole through the mast of the fuel selector, also failed to reveal a previous roll pin installation. Additionally, lockwire material was recovered from under the yoke of the selector detent plate. The lockwire that should have been secured to the yoke was missing. No record of recent maintenance was recorded in aircraft maintenance logs. A flow check of the fuel selector assembly disclosed that fuel flowed through the assembly without restriction. According to the annual inspection checklist, the fuel selector valve should be inspected for leakage. security, freedom, proper detent, and condition. A current annual inspection had been accomplished on the airplane. Reportedly the pilot performed the annual inspection under the supervision of an Authorized Inspector (AI).