? sealing leak at neck of fuel tank

[webhendrix]

I had replaced my fuel tank earlier this summer and had filled it up for the first time today (as I had not been driving it yet, just working on it) and noticed that it will leak from the weld where the neck goes into the tank (on the back side of the neck).

Is there anything I can seal that with?

To me it is a very small minor leak which can be avoided by not filling the tank up all the way but now I would guess that it would not pass the pressure test when I take it to the VET.

The other problem is my full gauge reads empty and the sending unit is new (and in good position) and the wire is new. When I have the wire off of the tank the needle goes way pass the full mark but if I put the wire back on, it slowly goes back to the empty mark???

Thanks for any tips!