DURING THE TAKEOFF ROLL, THE PILOT EXPERIENCED A PARTIAL POWER LOSS AND ABORTED THE TAKEOFF. HIS AIRCRAFT ROLLED OFF THE END OF THE DIRT RUNWAY AND COLLIDED WITH A PARKED COMBINE APPROXIMATELY 200 FEET FROM THE RUNWAY END. THE ENGINE WAS EXAMINED BY FAA INSPECTORS. INSPECTED COMPONENTS INCLUDED THE TURBOCHARGER, FUEL STRAINER, FUEL MANIFOLD VALVE, PLUGS, MAGNETOS AND CYLINDER ASSEMBLIES. ALL WERE FOUND TO BE IN GOOD CONDITIONS.