Do you mean port A on the tractor?If you cant fully close that valve something is still wrong. You are deadheading the pump sonewhere and you do not want to use it like that. You will pay the price in $$$.
Lets try to verify the neutral circuit on your valve is properly connected. Remove the upper hose from the hydraulic block and put it in a clean bucket. Start the engine and you should get a steady flow of oil with no pump strsun or whine. Do not run the engine for more than 30 seconds.
Dan