As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STUDENT PILOT ON SOLO CROSS-COUNTRY EXPERIENCED ROUGH ENGINE OPERATION. AIRCRAFT RETURNED TO AIRPORT. INSPECTION REVEALED PRIMER LINE ASSY AT NR 2 AND NR 4 CYLINDERS SEPARATED AT SOLDER JOINT OF THREADED CONNECTOR OF CYLINDER. FRACTURES ARE CONSISTENT WITH CYCLIC FATIGUE. SUBMITTER RECOMMENDS SECURITY INSPECTION ANY TIME COWLING REMOVED. TOTAL ACFT TIS: 5,554.0 HOURS ESTIMATED.