Oh.. I already have the flange bolts taken care of in exactly the way that you describe. The insulator is also not damaged, but the paper/cardboard gasket is simply missing. No diagrams I could find showed that there was a gasket here to begin with. I'll make one myself next time rather than use RTV. I have plenty of coated cardboard around.

I have looked at the PZ19 carb. Is this the one you're talking about?