Carb/flooding issue

[sportpsyc]

This is the newer of the two GZ250's I have--an '06. I just got it running after it sat at the previous owner's for 7 months. It fired right up after I primed it, and ran fine for about 5 minutes, but now it is very sick. Gas is literally pouring out of the drainage hose (the one routed down behind the engine between the arms of the swing arm). It won't run, and is flooded. I took the carb off thinking the float was sticking, but it was clean and seemed to be working fine (he had drained all the gas from the carb when he stored it), and the needle was free and moving up and down with the float. I cleaned it all out good with carb/choke cleaner, reassembled it, and got the exact same thing. Is the gas coming form somewhere else in the carb? Is there maybe some trash I missed in the needle valve seat, or could it be something else from sitting so long? The gaskets looked good--not dry or rotted, and the diaphragm looks good--no holes and still soft. There wasn't any discernible gunk or build-up anywhere I looked, and the jets were great.

Any suggestions? I guess the good news is, I can take that dang carb off and re-install it in under 5 minutes now! :-)