i have a 1991 blaster for a week and i wanna adjust the idle screw there is a small one kinda sunken in i belive is the carb then next to it is a big gold screw i think one is idle and one is mixture or somthing i dont have a manuel and the one i saw on here says its like under the seat? i dident see anything at all that made no sense to me please help what one is it and how do i adjust it ?