I have a Goulds model Jo5,worked great when I removed from sons house about 6 years ago. Want to take this to my camp to pump from lake. I hooked the pump up, with foot valve and put valve in a 5 gal. pail of water, to see if it still worked. primed pump and it pumped great, with out a tank. It built up to 36 lbs. and won't shut off. It will pump water all day, but shut the hose off it keeps running at 38 to 38 lbs and will not shut off. what am I doing wrong? Or do I need a tank hooked to it?