Briggs. I'm assuming 25hp V-twin.
Nikki carburetor aren't they?? Take it off, throw it into the next county and buy another carb. And gaskets.
Did many of them. You can clean them til you're blue in the face and sometimes they just don't cooperate.
Those were the only carbs I never could figure out. Maybe I'm just dumb. But at $100/hr shop labor, it don't take long to pay for a whole new carb.