When I have the carb off the engine and check for open an closed float valve, I do this. With it fairly dry I have the bowl off and see that mechanically the float and valve work, but also hold the carb up right and level and blow into the fuel inlet. I expect to hear a hissing as air from my breath goes through the carb. Then I turn the carb upside down and level and do the same and expect to not hear any hissing of any air going through the carb. My breath in my lungs should not escape any in this case. If it does, then the valve or the seat could be worn. Some seats are replaceable. Looking at the valve and seat with a 15x magnifier might show pits in the seals.
To note that this only lets me know that the float valve can stop the fuel flow, but the height of the float adjustment is something that is an adjustment that also may be necessary. The measurements and adjustment for that others would maybe have a better idea. I usually end up taking it apart and putting it back together again a few times to get it right if it is not set right.
I know this additional comment may not help now, but just thought worth mentioning anyway. If you get into working on engines enough and have another whole running engine of the same type, you can be more assured that a part off of the running engine swapped into the problem engine can at some point be better than a new part. I just got a whole new carb for a weedeater 2 stroke engine and noticed it has what looked like fuel in it. I would hope that it was just tested and would have been better if had been dried out too. If it was used, I could not tell that it was worn in anyway. Still too hot to go outside yet to work on it unless I get up real early. Going to 110 is no time to mess around with this.