As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT EXPERIRENCED ROUGH RUNNING ENGINE AFTER DEPARTING AIRPORT. PILOT RETURNED TO AIRPORT AND HAD MAGNETOS CHECKED. BOTH MAGNETOS WERE SEVERELY CORRODED INSIDE. ONE MAGNETO WAS DEAD. PILOT ELECTED TO REPLACE BOTH MAGNETOS WITH NEW UNITS. THIS IS THREE MAGNETOS IN TWO MONTHS. SUBMITTER SUGGESTS PROBLEM IS CAUSED BY TURBOCHARGER PRESSURIZING AIR AND MOISTURE.