Since you stored the engine and maybe didn't run it dry, plus probably left it hooked to the tank, the regulator needs to be taken apart and cleaned and possibly needs gaskets and diaphragm replaced. The fuel passages may be clogged as well. Before doing all this, try opening the main needle about 3 turns and running it at full throttle for a tankful of fuel. If it dies rich close the needle down and try again until it will run at full for the whole tank. Might fix it.