On March 25, 2013, about 1300 mountain standard time, an experimental Owens Velocity 173 airplane, N33SV, experienced a loss of engine power during cruise flight and the pilot made a forced landing on a dirt road near Maricopa, Arizona. The pilot/owner operated the airplane under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. The pilot and two passengers were not injured; the airplane sustained substantial damage to the wings and fuselage. Visual meteorological conditions prevailed for the local area flight that departed the Pegasus Airpark, Queen Creek, Arizona, about 1230. No flight plan had been filed.The pilot reported that the airplane was airborne for about 30 minutes when the engine began to run rough followed by a loss power. He attempted twice to restart the engine, but was unsuccessful. The pilot identified a dirt road as a landing spot and performed an emergency landing. During the landing rollout the airplane struck an irrigation pipe, departed the road, and came to rest in an open field. Postaccident examination revealed that the fuel tanks contained 20 gallons of fuel; additionally, the engine controls and fuel selector continuity were established. The ignition system, primary fuel system, and drive train were examined and found to be functioning normally. After several unsuccessful attempts were made to start the engine with the modified Ellison throttle body attached, the throttle body was then removed and the engine started successfully. An examination of the throttle body revealed no anomalies that would have precluded normal operation.