RE: Got my G-45 today NO SPARK
The black wire should be grounded when you wish to kill the engine. If you are using the zenoah switch harness that horizon markets for these engines, the switch is marked backwards. They use a generic switch that is marked "on" when the ground circuit is made. The engine will not run when ground is present of course, so it should really read "off" when it is "on". Got that??
If that is not your problem, there are troubleshooting steps in the manual that may help.