No experience with that machine but any time I've seen a carb leaking gas from anywhere other than the float bowl gasket, it's been because of a problem with the float valve or float height adjustment. Either of these can cause it to allow too much fuel into the carb and it has to go somewhere from there. You might want to post this question in the ATV section and see if anyone there has any advice.
I have had this happen on multiple occasions. It usually does it when I am going down very steep declines. The dealer says this is normal and make sure not to over fill the tank. I have talked to a few other Brute Force owners here in NW Arizona and they have the same problems when riding in the mountains.
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