Starter not disengaging?

get under there with the inspection plate off and manually pry the pinion gear out to mesh with the ring gear. Does it go all the way out? Remove the small wire to the starter and check for voltage in start (good) and run (bad). Larger wire will always have power. These starters have a contact on the fork that moves the drive gear out to the ring gear. As soon as the solenoid is energized, the electomagnetic force pushes the fork out and makes this contact bridge the power connector to the motor. The contact is closed and the starter motor spins. The only switched voltage the starter needs is the relatively light solenoid load, that closes the contacts for the much higher amp draw starter motor. Hope this helps in diagnostics. check for lingering voltage at the solenoid after the ingnition switches back to run from start. Could be back feeding from somewhere. .