on the inside of the tank.. is the tank rusted or has it fallen in from inside?... strange to have rust on the inside.. id say bin it if its rustin the actual tank
Its powder like surface rust, no hole or anything it can be scrap off. Anyway I think I've just found a solution there is a fuel tank repair kit you can buy that remove rust and create an enamel type coating inside the tank. I think I will give it a try.