dried out

My 88′ trx fourtrax 300 2×4 is running great but when I let it sit overnight it will not start unless I spray carb cleaner, starting fluid or etc.. in the air box it runs great after that and idles good etc.. I rebuilt the carb a couple summers back, I wondered if maybe the float was letting the gas siphon through and emptying the bowl. Any ideas?

thanks’
Dave