Help an idiot fix his carb

I feel like the biggest dumb as*! I am in the process of rebuilding a thermoquad i bought several years ago at a swap meet. The boss where the idle speed screw was not drilled for a screw from the factory, so i drilled and tapped the hole for the screw. My idiot self drilled the hole crooked so now the screw misses the arm that its supposed to touch to hold the throttle plates open! If it were regular metal i would just have the hole welded back up and re-drill and tap it again, hopefully straight, but im sure this pot metal or whatever it is cant be welded. Any ideas of a fix?
Thanks!