Weed Eater Riding Mower Chokes Out and Stalls

I have an older Weed Eater riding mower that will start with the throttle down without a problem, but when I throttle up, it chokes out and stalls. It has an auto choke. I've tried adjusting the idle, but it does the same thing. Before it dies the choke "bounces" back and forth.

By Mike