On October 19, 1997, at 1030 eastern daylight time, a Cessna 150M, N7814U, collided with a palm tree during a forced landing to a golf course on Fisher Island, in Miami, Florida. The personal flight operated under the provisions of Title 14 CFR Part 91 with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane sustained substantial damage. The private pilot was not injured, but the passenger received minor injuries. The flight departed Miami, Florida, at 1020. According to the pilot, about 10 minutes into the flight, at a cruise altitude of 1000 feet, he experienced a loss of engine power. The pilot radioed a "mayday" call and selected a nearby golf course for an emergency landing. The airplane collided with a palm tree during the emergency landing roll. Examination of the aircraft at the accident site disclosed that flight and engine control systems operated normally. Examination of the engine assembly revealed that number one cylinder lower spark plug was partially separated from the cylinder. There was also engine oil noticed inside the lower engine cowling. Attempts, to rotate the engine through one complete revolution, failed. During a subsequent engine teardown, the number one exhaust valve stem head was recovered from inside the cylinder. The examination of the exhaust valve stem and the valve stem keepers showed excessive wear. The valve stem keepers had separated from their normally installed positions. A review of the aircraft maintenance logs disclosed that the engine had undergone several major engine repairs, involving the valve assemblies, within the last ten years. An engine top overhaul was completed 370 hours before this accident. The engine had accumulated a total of 5,603 hours.