On site we have a GE 9FA DLN2.0 gas turbine, dual fuel. The liquid fuel system was left out of operation from 2007 and afterwards. It run only for 30 hours in total. Now we need to make recommissioning, one of the items to do is to rotate by hand the main motors: liquid fuel pump, atomizing air compressor, water injection pump. The liquid fuel pump is a IMO positive displacement pump, by hand is stuck and can't be rotated. We uncoupled from motor, motor rotates properly but the pump is stuck. Can you suggest how to proceed?