Weedeater XT 300 Carb adjust

If my memory serves me correct, one is for fuel/air mixture and one is for the idle speed. Be careful adjusting the fuel/air mixture, if you run it too lean the engine won't get enough oil via the fuel and it's will destroy it. Was it running before you played with the adjustments?

One is probably idle, the other high speed mixture. Turn them both in all the way then back out 1.5 turns and give it a try.

It was running last year, but I rarely used it and as i recall, not very well, I can only turn the one plastic screw maybe 1/4 turn from centre? I assume this is the Fuel /air mixture adjust? It is at the cottage so I will try another spark plug and play with it on the weekend. I was getting it to run at full choke and 1/2 choke on the weekend?

Well each brand carb has it's own requirments. I use Echo tools here and was giving advice based on those. Hope you get it sorted out.

The plastic part is a limiter to prevent you from making a proper adjustment. Take needle nosed pliers and tear the plastic part off then you can proceed with a proper adjustment. One is idle mix, the other is high speed mix. They must be worked together. One affects the other. They should be marked on the shroud or other plastic parts as to which is which.