As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CARBURETOR HEAT TUBE ERODING DUE TO SUPER HEATED AIR FROM MUFFLER SHROUD. TUBE WIRE SUPPORT AND DEBRIS FROM TUBE COULD BE INJECTED DIRECTLY INTO CARB AND ENGINE. DIFFICULT TO INSPECT DUE TO FIRE SLEEVE WRAPPED AROUND TUBE. SUBMITTER SUGGESTS DIFFERENT TYPE OF TUBE OR MATERIAL.