Abstract: An externally adjustable liquid interface for a centrifugal separator. A tubular liquid outlet extends into a rotatably mounted drum. The tubular liquid outlet has an exterior surface, an interior bore, and a top lip which represents an interface for liquids of differing densities. The tubular liquid outlet includes a first tubular member and a second tubular member. A first end of the second tubular member telescopically mates with a first end of the first tubular member. A second end of the second tubular member serves as the top lip of the tubular liquid outlet. A threaded coupling is provided between the first tubular member and the second tubular member. Upon rotation of the second tubular member the relative telescopic position of the second tubular member and the first tubular member is altered. A fitting disposed in the interior bore of the tubular liquid outlet is non-rotatably coupled with the second tubular member. The fitting is adapted to receive a working end of a tool.