Starter stays running

I have an 85 F100 with a straight 6 that the starter motor stays engaged when you start the truck. The starter and the solenoid have been replaced. I disconnected the starter side of the solenoid and connected a digital multi tester to it. When you turn the key all the way to start, the tester reads 11.9 volts. With the key released, it reads .1 volts. Does this sound like a bad starter or solenoid?

Thanks.

The only way the starter can stay engaged is
a: if youre still getting power thru the solenoid after the key is released
b: the starter drive (bendix) is staying engaged because of a mechanical problem in the starter.
c: wrong starter, and the drive is staying in contact with the flywheel
Hook a test light, or meter, to the starter side of the solenoid, start the truck, and see if you still have voltage after you release the key with the truck running. If you have no voltage, its a starter problem. If you have voltage, the solenoid is either sticking, or staying engaged because of a bad ignition switch, or a wiring problem. Check for voltage at the small terminal on the front of the solenoid, with truck running after key is released. This is the wire that energizes the solenoid, and it comes from the switch. This is all assuming that everything is wired correctly.