As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER SHUT DOWN, THE ENGINE COULD NOT BE STARTED. NO FUEL PRESSURE COULD BE PRODUCED. SUBSEQUENT INVESTIGATION REVEALED THE LOCK NUT RETAINING THE MIXTURE ARM ON THE METERING UNIT SHAFT HAD LOOSENED. THE SHAFT COULD NOT BE ROTATED WITH THE ARM UNTIL THE NUT WAS RE-TORQUED TO 100-120 INCHES/POUNDS.