Emery Rudolph

Hello, I just purchased a Poulan Pro riding mower, model PP175G42 in May 2016 and I am experiencing problems with the choke. The mower is supposed to be operated in the full (fast) position and did so properly the first couple of times, but now if immediately dies when the choke is moved just past the center notched position. I made a Youtube video showing this behavior. I would appreciate any assistance with understanding why this is occurring.