85 fuel tank leaking?

[Finster]

Do you have fuel in the bilge? And how did you check your fill and vent? Their both tough to do a visual on.

I ask because my '78 had that problem and as it turned out the fill and vent were shot and the tank was 100%(which is uncommon for a '78 tank).

I've had other boats with screws threw the fill, leaky sending units, stuff like that. I'd change your fill and vent lines, check your sending unit and go from there. If you need to change your tank your gonna want to replace those lines anyway.