As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER 3.5 HRS POST EXHAUST SYSTEM OVERHAUL, THE MUFFLER HAD A CATASTROPHIC FAILURE WHERE SECTION OF MUFFLER DEPARTED ASSEMBLY DUE TO INNER BAFFLING FAILED DUE TO MISSING WELD. AIRCRAFT WIRING WAS BURNED ON LT SIDE OF ENGINE (STARTER WIRE) CARBURETOR BOX WAS TORCHED AND BURNED, WITH EVIDENCE OF FIRE ON ENGINE AND ENGINE COMPARTMENT.