On May 30, 1999, about 1250 eastern daylight time, the certificated airline transport pilot/owner was seriously injured when the engine inadvertently started while hand rotating the propeller of his Nanchang CJ-6A, N4M, at the Ocean City Municipal Airport, Ocean City, Maryland. A passenger in the airplane was not injured and the airplane was not damaged. Visual meteorological conditions prevailed and no flight plan was filed. The pilot was preparing the engine for start with the intention of flight to be conducted under 14 CFR Part 91. In a written statement, the pilot said: "I had flown a local sortie out of Ocean City Airport earlier that morning. My intention was to fly a second sortie in a two-ship formation with another FAST qualified formation pilot flying his YAK-52. I had to wait approximately 35 minutes for fuel after the first sortie. We conducted a formal briefing for the formation flight and my back-seater from the earlier flight and I strapped into my airplane. I accomplished the "before starting engine" checklist and then looked over my shoulder to see if the other aircraft was ready to go." At this point the pilot aborted the engine start procedure. The pilot was concerned that oil was accumulating in the lower cylinders, and the potential of internal engine damage due to hydraulic lock during start of the radial engine. He then exited the airplane. The pilot further stated: "...as a precaution, I decided to pull the prop through to assure myself that I did not have a hydraulic lock situation. As I pulled the prop through from the 3 o'clock position to approximately the 6 or 7 o'clock position the engine fired and began running, catching me off guard and throwing me to the ground. When I aborted the start and shut down the electrical systems, I had overlooked one switch, the magneto. The magneto switch was in the "both on" position and therefore the mags were hot. All the elements were there for a successful engine start: fuel, air, and spark." The pilot reported there were no mechanical deficiencies with the airplane. He also reported a total of 11,500 flight hours which 350 flight hours were in make and model. The pilot acknowledged that all switch positions should be double checked to make sure the magnetos are not on prior to touching the propeller.