What was found
(CAN) THE ENGINE HAD 6 HOURS TTSO. THE PILOTS NOTICED AN ENGINE VIBRATION, AND STARTING WAS BECOMING EVER MORE DIFFICULT. THE AME THEN PROCEEDED IN REPLACING THE TWO MAGNETOS AND THE CARBURETOR. AFTER A FEW HOURS OF FLIGHT THE PROBLEM PERSISTED. THE AME THEN CONDUCTED AN INTERNAL INSPECTION, IT WAS REVEALED THAT THE INTAKE VALVE IN CYLINDER NR 1 AND THE EXHAUST VALVE IN CYLINDER NR 3 WERE NOT OPENING COMPLETELY. AN INSPECTION OF THE CAMSHAFT WAS CARRIED OUT, 2 LOBES OF THE CAM WERE DAMAGED. THE ENGINE WAS REMOVED FROM THE HELICOPTER AND THEN THE CAMSHAFT WAS REPLACED UNDER MANUFACTURERS WARRRANTY.