The plane had been involved in a bankruptcy settlement and had not been flown for about 3 1/2 months. The pilot had been sent to ferry the plane. During a run-up before takeoff, the propellers moved toward a feather position without pilot input. The pilot had a mechanic service the props. A subsequent run-up was normal, so the pilot took off. About two minutes after leveling at 1800 ft, the left prop started feathering again without pilot input and the left engine lost power. A short time later, the right engine began losing power. An emergency landing was made on a closed airport; however, the gear struck rocks and debris that were not visible in an area of grass. An investigation revealed the engine oil had not been changed since 7/20/81. The prop governor screens were found with about 70 to 80% blockage with a carbon build-up. An oil analysis revealed a high aluminum content. The lab report stated that this may be from break-in, recent maintenance, abnormal wear, or over extended oil drain. Last annual dated 4/2/81.