Greetings! Newbie here with what must be the #1 question you guys get here....Why won't my stove hold pressure?? Primus 210 made in 1943. Got it lit fine but when pumped up it quickly loses pressure and goes out unless I keep pumping. It seems to hold pressure better when the pump handle is held in as otherwise the pressure pushes it out and that's where it must be leaking?? I did put some oil on the leather washer. Maybe needs to be changed?? Any help greatly appreciated. FB in Vt.