Outdoor Power Equipment and Small Engines - Crafstmen blower issue

I have a Craftsmen blower issue. Originally I thought the head was lose on it howerver this was not the issue. It was actually the mufller bolts loose and causing some rattling noise. Anyways, the following issue seems to be happening and it appears there is no carbuerator adjustment on these. When you run the blower it runs fine for about the first 45 minutes of continuous useor one tankful of gas. I then put more gas in it and try the blower with the choke totally off and the blower will not run. it will start fine for a second then start to die, if I immediately turn the choke lever to half choke the unit will run fine however, the power does not seem to be there. Any thoughts why at this point he unit will not run unless the choke is on a bit.

Probably an air leak into the crankcase. The plastic used on these low end 2-strokes can warp when it gets hot and allow air to leak into the crankcase, creating a lean running condition. The crankcase cover bolts might just be loose, like the muffler bolts and head bolts were. The heating/expansion, and softening of the plastic when hot would contribute to the problem. This probably occurs when you run out of gas because by then the heat has built up in the engine well, and the fact that when it runs out of gas, it runs lean for a short time. An engine runs much hotter when it runs lean, so it is getting hotter than normal those last few minutes or so as it is picking up air through the fuel pickup.