Aleecat,
open fuel path will not cause the pump to have increased current draw requirement, actually, just the opposite. ALL motors have start up resistance that must be overcome. All motors draw higher current at start up than while running.

More than likely the contacts to the fuse or relay have become corroded or oxidised. a poor connection will cause heat as a byproduct. The best way to keep cool is keep the contacts clean. Use electrical contact cleaner. It comes in a spray or a liquid that you have to apply.

It may also be that your fuel pump relay itself is causing added current draw through the fuse, as the relays are always a prime candidate for the owl solder gun technique so many rave about.

You didn't say anything about your secondary fuel pump making excessive noise, wich would rule out a grounded main fuel pump.

Good luck, hope this helps