The HALL SENSOR (it goes by many names) is the sensor near the prop hub. It is a magnetically triggered switch. The magnet is IN the back of the prop hub. If you have no ground and try to run the engine, it is possible to damage the ignition module. The best thing you could do now is to mount the grounding strap on the plug ( I use a hose clamp and clamp it to the HEX part of the plug) and try to run it, see if it fires. leave the plug out of the engine and crank it over with the ignition on, check for spark. If it fires, put the plug in and run it with the ground strap hooked up like this, see how it runs.