Weedeater Won't Keep Running?

My weedeater (Twist & Edge TE 400 LE) is having trouble starting. When it does start in the full choke position it runs for a short while but then quits. If I get it started and move it into the half choke position, it slows down and then quits. If I put it in the no choke position it immediately dies. Seems like it is not getting fuel but the tank is full. Any ideas???