Abnormal engine indications involving a The Boeing Company 727-77, VH-TBS, Sydney, NSW on 18 December 1992

The number 3 engine began vibrating on climb through FL340. The vibration could be felt through the airframe. The N1 was reducing and fluctuating and the fuel flow was reducing. The engine was shut down and the aircraft returned to Sydney. Maintenance checks found water in the engine fuel control unit. When this was drained the engine operated satisfactorily. The source of the water could not be determined.