My recently acquired Solus Coleman USA will not pressurize. I think the pump leather may be bad but looks okay. When I pump the tank gets very slightly pressurized but the moment I stop pumping the pump handle pushes back out. The pump handle is solid, no hole in center. I’ve turned it every direction to see if it locks or unlocks but it spins endlessly in either direction. Should there be a check valve on the stem or inside the tank to prevent air pressure backflow? I’m stumped and can’t find a diagram regarding the pump assembly or if there’s a check valve in the tank. I’ve ordered leathers for the pump but assume the tank if pressurized will just push the pump handle back out. Thoughts? Ideas? Otherwise the stove is in excellent condition.