As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN-FLIGHT MIXTURE CONTROL WOULD STICK AND WOULD NOT GO BACK TO FULL RICH MIXTURE. PREVIOUSLY, MOISTURE STIFF BUT WOULD MOVE, AND INSPECTION FOUND NO PROBLEMS. AFTER LAST 'STICK', INSPECTION FOUND THAT IDLE CUT-OFF STOP PIN WAS LOOSE IN ITS HOLE AND FREE TO MOVE IN AND OUT OF ITS HOLE FAR ENOUGH TO BLOCK MIXTURE LEVER. REPLACED PUMP WITH NEW PART.