carb question on 4 stroke 97 gas
 

ok i have a simple guestion what is the litle black plastic adjuster for on top of the carb for is it the air screw???? i have cleaned my carb a few times and it doesnt want to run unless you play with the choak to get it going, when you just flat foot it it sputters, i bought this as a project and it does have old gas and new gas mixxed so that could be it too but i really would like to know where the air screw is if anyyone could help me out

97 ez go txt 4 stroke!!!!
before and after pics will follow soon thanks everyone