Not getting a spark!

I just swapped my old motor for a new one. And now the motor is not getting any spark. It did it once, then nothing. I don't know if the wiring for the distributor is mesesd up, but it worked fine on the old motor. Its a jap. exchange motor. Does anyone know if you have to use your original distributor or can you use the one that came with the motor?

thanks in advanced!