carburator adjustments on ryobi 766r,31cc gas weed eater?

I am trying to set the adjustment screws on the carburetor,the screws that have a red plastic cover on one and a white cover on the other that are right on top of the carburetor. Is there a standard to start with, like screwing them all the way clockwise and the turning them counterclockwise so far to start with until you get them adjusted where it runs properly. Iv'e tried this several times, but I can't seem to get it just right. It runs for a while then bogs down and dies, then I start it again and it does the same thing again.