The wire from you ignition switch to the solenoid is not getting fire to the solenoid switch. Check it for loose connections, shorts, breaks, etc. Grounding it out at the solenoid to start it simply means that when you turn the key to "start" position, the wire from the ignition switch should give current to the solenoid, and allow it to send current to the wire going to the starter, which is what you do when grounding it out at the solenoid to start it. Therefore if the wire from the ignition to the solenoid is not getting current to the solenoid, the problem has to be either the wire or the ignition switch itself, assuming the solenoid is good. You can do a simple test to see if the ignition is getting current when the key is in starting position, with a 12V test light. Put the alligator clip on a good ground, and the probe on the post where the wire connects from the ignition switch, and turn the key to try and start it. If you get a light, then the problem is in the solenoid switch. If you don't get a light, then the problem is in the wire or the ignition switch.