Outdoor Power Equipment and Small Engines - gas tank leaking, troy-bilt mower

i have an old troy-bilt self-propelled that i acquired for nothing from a friend cleaning out his garage. he tells me that he hadn't used it for a couple of years, but it always ran well. since he was just going to throw it out anyway, there was no reason for him to exaggerate.

but when i fill it with gas, the gas comes leaking right out onto the mower deck. it runs out quite rapidly.

i hate to pay to have the tank fixed only to find that there are other problems as well, since i don't even know if it will start at all. my question is this: is this the sort of thing that a fairly good around-the-house handyman with very little small engine experience might be able to take a stab at?

Are you sure it's the tank leaking and not a fuel line, or more likely: the carburetor?

What are the engines' ID numbers? Perhaps, since you said it was old, that this is one of the recall gas tanks from Briggs that dangerously and notoriously leaks.