Not sure what your calling a valve. The thingy with the spring is the needle valve and is used to adjust the RPM of the engine. The fuel tank has two nipples. One on top and the other on the bottom. Put fuel into the top nipple until the fuel runs out of the bottom one.

If your fueling the engine correctly, then you have a bad gasket between the engine and the tank. The tank may be loose as well. Another thought is that the needle valve is turn out too much. I can't recall the starting needle setting. Probably three or four turns out.