Mine will do the same thing after sitting for some time. For some reason it does not want to draw fuel easily.
I usually drain the fuel system and run all the gas out during winter lay-up. In the spring, fresh fuel is added.
I have to remove the air box cover and hold my hand or a rag over the the intake to the carb while using the electric starter. This creates more vacuum in the crankcase/carb to get the fuel flowing.
Of course, having fuel sit in the carb bowl for that long is not good. If the above procedure does not work for you, then you may have to pull your carb and clean it, add new fuel and try again.
