so on my 4 wheeler i just cot for my son doesnt idle and when i looked at it for the idle adjustment screw it looks like there are brass caps. not to sound stupid but you just drilled them out and the screw heads are behind?

 

if you look at the top photo it looks like a little brass nipple sticking out under the choke arm what is that?

 

Second photo down, dead centre of picture is the slow running screw, this you can adjust. The idle mixture screw has a brass cap over it to stop you messing with it. Leave it alone. Give the carb a good clean out, I go for removing jets and cleaning them, and the holes they came from, out with compressed air. My guess for the "little brass nipple" would be it is the pin to stop the throttle slide turning round, who cares anyway?