What was found
(CAN) AIRCRAFT LANDED DUE TO LOSS OF ENGINE POWER. INSPECTION FOUND THE NR 3 CYLINDER CONNECTING ROD WAS BROKEN. PILOT REPORTED A HYDRAULIC LOCK 14-19 HOURS EARLIER, AFTER THE FUEL PRIMER SYSTEM WAS WORKED ON. REMOVAL OF NR 3 CYLINDER REVEALED THE CENTER PRIMER INSERT MISSING. SUBMITTER STATED THIS POSSIBLY ALLOWED ALL PRIME TO BE DIRECTED TO THIS CYLINDER. MAINTENANCE CREW REPORTED THEY PULLED THE PROP THROUGH SEVERAL TIMES AFTER THE PRIME WAS WORKED ON. THE ENGINE WAS REPLACED.