Hey Steve, the spill jet isn't made to come apart, although I have taken one apart before. There is a small plastic ball inside that is forced up when the pump operates, closing the intake opening at the top, while allowing some of the pump volume to "spill" out the hole in the side. To clean it, back flush it with spray carb cleaner, both from the intake and the side. The ball should be free to move. If the spill jet is not working, it will affect both sides of the carb. Look into the throat that is leaking; if there is a steady drip coming from the pump nozzle when the motor isn't running, the problem is likely with the delivery valve ball not sealing.
As far as the engine racing, check for vacuum leaks between the carb and manifold, and also make sure the starter valves are fully closed.