I just put a new carb on my trimmer because it was running bad, it would idle up and down and just die. I put new fuel in it and cleaned the carb but no luck,so I replaced it. Now it won't stay running. I start full choke then half choke it runs for 2-3 min and shuts off. Won't run at all in no choke. Do I need to adjust something or what?

Your mixture is way too lean, that's why choking the air can get it running a little. You need to back off the mixture screw at least 1/2 turn and maybe more.