As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ANNUAL INSPECTION, IT WAS NOTED THAT THE RIVETS THAT SECURE THE CARB HEAT VALVE PLATE TO THE CONTROL CROSS SHAFT WER COMING LOOSE. THIS APPEARS TO HAVE BEEN CAUSE BY SEALING MATERIAL ON THE VALVE PLATE WHICH WAS NOT CORRECTLY TRIMMED. AS A RESULT, THE MATERIAL WOULD BIND IN A CARB HEAT NEEDED POSITION, MAKING IT DIFFICULT TO RETURN THE VALVE TO A NO CARB HEAT POSITION.