As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING ANNUAL INSPECTION, A PRESSURE TEST OF THE ENGINE FUEL SYSTEM REVEALED A LEAK AT THE MIXTURE CONTROL SHAFT WHICH DRIPPED ON THE MUFFLER BELOW . REPLACEMENT OF O - RINGS 953516-10 AND 951401 CURED THE LEAK. SUBMITTER SUGGESTED CLOSE INSPECTION AND PRESSURE TESTING SHOULD EASILY FIND THIS PROBLEM.