A well fluid centrifugal pump has a shaft passage in the shaft. The shaft passage has an open upper end above the impellers and a closed lower end below the impellers. An outlet port extends laterally from the shaft passage. A gas-lock re-priming device in the shaft passage diverts a portion of well fluid in the discharge adapter bore through the shaft passage and out the outlet port. The re-priming device may be a pressure actuated valve that is biased to a closed position and opens when the pressure in the discharge adapter bore drops below a minimum. Alternately, the re-priming device may be an orifice member with an orifice passage that continuously diverts a portion of the well fluid in the discharge adapter bore out the outlet port.