On September 24, 2015, about 1050 eastern daylight time, an experimental amateur-built Sport Copter Vortex gyroplane, N179V, was substantially damaged following a collision with terrain during a forced landing near Lake Wales, Florida. The sport pilot sustained minor injuries. The gyroplane was privately owned and operated under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions were reported at the airport about the time of the accident, and no flight plan was filed. The personal flight originated from the Lake Wales Municipal Airport (X07), Lake Wales, Florida, at 1045.According to the pilot, he conducted an engine run-up prior to takeoff and all systems were normal. During the initial climb, he made a left crosswind turn and climbed to approximately 300 feet. He noticed that the engine began to lose power and made a left downwind turn in an attempt to return to the airport. The engine continued to lose power and the pilot attempted a forced landing in a field. During the landing sequence, the gyroplane rolled over and sustained damage to the airframe. An examination of the gyroplane by a Federal Aviation Administration inspector revealed that the fuel line on the primer valve was brittle and disconnected. The primer was operated and fuel was noted to leak from the primer fitting. In a conversation with the pilot he said that all of the fuel lines had been previously replaced except the primer line. Correspondence with a representative of the engine manufacturer revealed that a breached primer line can create a lean air/fuel ratio, thus resulting in a loss of engine power.