Sounds like a possible kill switch between the key and the push button, or a bad wire. �If I understand your description right, I think you might have a few things miswired. �You should have power coming from the battery to the starter relay and then to the ammeter. �From the ammeter, you should have power going to the headlight circuit, horn and to the ignition key. �From the ignition key, power should flow when in the ON position to the fuel sending unit, the push button and the coil. �From the push button to the starter relay. �That way only of the key is turned to ON can you push the push button and turn over the engine. �But, your lights and horn will still work when the key is OFF. �