THE PILOT'S IMPAIRMENT OF JUDGMENT AND PERFORMANCE DUE TO DRUGS, HIS FAILURE TO ABORT THE TAKEOFF AFTER EXPERIENCING REDUCED TAKEOFF PERFORMANCE, AND HIS FAILURE TO MAINTAIN MINIMUM CONTROL SPEED. FACTORS IN THE ACCIDENT WERE: A PARTIAL LOSS OF ENGINE POWER DUE TO IMPROPER MAGNETO-TO-ENGINE TIMING, AND A PARTIALLY BLOCKED FUEL NOZZLE.