Tecumseh Carb Leaking from Mixture Screw

Hi, I have a Tecumseh Series 1 carb on a 7 HP Snapper snowblower that’s leaking gas on the bottom of carb. It appears to be leaking around the main mixture screw on the bottom of the carb. It’s not leaking around the bowl nut. I’ve replaced the o-ring on the mixture screw and also replaced the entire mixture screw/bowl nut assembly with a new one. Float level has also been checked. Gas still appears to be leaking around the mixture screw. Any idead how to eliminate this leak or what else to look for? Thanks in advance!