331877 089 G5 is missing a digit. Appears to be 331877-08
69-G5.

If you have a Nikki carefully change the float bowl gasket set.
The o-ring circled in the following tends to be where the fuel is at. But damage to the either gasket will cause problems, even just a nick or defect can cause problems. The circle o-ring is the one that goes around the fuel inlet tube and is before the needle valve.

Now Briggs did change to a Ruixing carburetor after date code 15112900 but the OP didn't the date code. Which leaking fuel after verifying the needle is in good shape and a new needle installed would require replacing the carburetor.