Hi fellas, I’m fettling an old Coleman, the fuel pick up bung on the tank it was roughly soldered , I hid clean it up / off a bit to see what was there, My question is dose the bung need to be silver soldered or just lead soldered Any advice much appreciated
Because it's more to make a seal than contribute to structural integrity ordinary solder will do just fine.
Soft solder / plumber's solder 60/40, 50/50 or most anything thereabouts. I've got several 1920s vintage stove where the fuel tank is a cylinder with the main seam and ends soft soldered together.