Are you using an electric starter? If you are trying by hand you may be turning the prop in the wrong direction. As your looking at the plane it should turn counterclockwise. Also look to see if it is taking in fuel. Do you have the vent tube hooked up to the muffler? It should be. Are you sure you didn't mix up the fuel lines? I've done this. Switch them and see if thats the problem. If your using the vent to the carb it can't get fuel. Make sure your glow igniter is charged. I hope this helps and you get it started!

Gibbs