I don't know what ignition comes with the SPE but if it has a sheilded plug cap that locks onto the it does not need a ground wire, I thnk some of the earlier ignitions that came out of China had a ground wire (not the RCxel)

Most engines when new are hard to start untill you get a tank or two through them.

If it has a shielded plug cap, Remove the plug from the engine and install in to the plug cap turn on the ignition and rotate the prop to see if you get fire.

Milton