The Cline regulator is not a pump, it is a demand regulator. My H-9 P-47 will (with the feed line disconnected from the engine) empty the tank due to siphon efect. Try this: disconnect the feed line (the one that goes to the carb) and put the end into a container that will catch the fuel.(try to keep the end of the line at about the same level as the carb is) Attach your fill from your field pump to the fill line, and begin to fill the tank. when the tank is full there will be some fuel come out of the feed line. See if the tank empties. If it does, you will need some type of regulator (not a Perry pump) If the tank does not siphon itself empty, then you either have a mix up on the plumbing, or a bad glow plug, or mechanical mis adjustment of the carb.