Carburettor "fuel inlet" thread broken what can I do?

I recently got the Malossi 13/13 carburetor and installed it. When I tried to tighten the "fuel inlet" (I'm not familiar with the technical term, but I've attached a photo below), the ratchet suddenly started spinning, even though I hadn't even screwed it tight enough… I unscrewed the screw again, and a spiral came out…