Did you use two filters? one between the engine and the check valve and the other between the tank and the regulator?

You obviously don't have any dirt in the check valve, but your regulator may be full? Why don't you check your tank pick-up clunk and connections before you go tearing into the regulator?

If you do go into the regulator be extremly careful to put everything back exactly as it came off. Minus any dirt or lint that is.

good luck

Jim