Need help with carb problem

Hi all, thanks for this great forum.
I have a 1998 TRX 300 4X4 that bought new, it has never been beat up. It has been sitting most of the last 10 years so I rebuilt the carb and gave it some fresh gas. When I start it with the choke on it runs good but as it warms up when I move the choke to half still OK but when I try to move it back any more it stalls right out. What have I done wrong? Any HELP please.:confused::confused: