Back it out and put just a touch of grease on the threads and tip. Make sure its in neutral and there is no load on it. It just pushes the movable pulley away from the fixed pulley..the one with the threads. IF it won't move, it's likely some parts of the blown belt are jammed in the hub. Don't force it but if it doesn't open smoothly, pull it and disassemble it. Probably fine cords and rubber binding it.