The pilots reported that they were unable to change engine power via the throttle while attempting to land, which resulted in an off-airport landing. During the landing the airplane’s left wing was substantially damaged. One of the pilots described that this was the second flight of the airplane after it had undergone extensive maintenance, which included installing a newly overhauled engine and an annual inspection. Postaccident examination of the engine found the hardware used to connect the throttle cable to the carburetor was missing. A review of maintenance records revealed that the throttle control was rigged during the annual inspection. The mechanic who signed off the annual inspection said that he and several other mechanics had conducted extensive maintenance on the airplane, and they had most likely forgotten to install the cotter pin that would have secured the throttle cable to the carburetor. Given this information, it is likely that the throttle cable detached from the carburetor during the flight, which resulted in the the pilots being unable to control engine power, and the subsequent off airport landing.