It is called Acheson Colloids Emralon, a PTFE dry film lubricant in a phenolic or epoxy resin. Back in some older posts a member had his shafts coated with Cerakote ceramic coating. Like was said in that post-when the coating wears off, then the shaft itself wears and it will never be perfect again even if the carb is rebushed. Rebushing helps. I use a thinwall brass bushings to do the Thermoquads.