Unclejesse

Hi so I just picked up a 2018 evo80 Jr for my son.. bought it off the original owner who son rode it twice and never again and it has maybe 8hrs on it .. it had sat for atleast 4 years it wouldn't idle at all when we went to look at it and pulled the carb off and cleaned it all out and it runs much better but still is struggling idling for any period of time and stalls out . Ive played with the mixture screw and had varying results and it seems to run better for abit then not .. it runs great off idle so im not sure where to go with it ...plug looks good . Fuel supply is good. Airfilter is freshly cleaned and oiled. Im wondering if maybe its a jetting issue ? We are below 1000 ft from sea level ... carburetors are not my strong suit lol Cheers