The XZ is very tight when new. Heat it like the others have suggested. Also, take the plug out put a couple of drops of after run or fuel in the cylinder to help it turn over on the box until it draws enough fuel to start. Mine was super tight when I got it and even after 2.5 gallons it still sticks sometimes when it's cold. You will be very pleased with the power though once it's broken in, just have patience and it will loosen up.
Futaba, O.S. Engines, Tornado Fuel, Schumacher Racing, SpeedPassion USA, Eggroll Inc., Desoto Racing, Vesselli Racing