I'm having a weird situation where my starter solenoid engages briefly when I turn the ignition to the on position. I can hear it click out, then immediately back in. When it clicks out, I can see the fan move slightly as the gears try to mesh with the flywheel. It doesn't seem to be an issue for starting since it returns back to its safe position, but I don't know why it is happening. I have tried two different starters, and two ignition switches, but the solenoid reacts the same way every time. Any thoughts? This is on a '76 with a 2F.