I have had pretty good luck making up a new screw.

I roll a piece of copper screen around a nail (used as a form) with some overlap of copper screw.

I then use a large wattage soldering iron to run a bead of solder.

I pinch the end at the top and solder it as well.

I then use JB Weld to insert it into the original brass piece.

I do use an inline filter while running the motor initially until the tank gets clean.

Fine fouling from the tank can still pass through the copper screen so you might have minor periodic problems if you run the motor a lot.