Have an '88 Evinrude XP200 (STL). I can turn off the key and pull it out but the motor does not stop running. It does slow down a little but does not stop unless I drop it in gear to kill it. Buddy told me stop circuit was going out. What exactly is the stop circuit and how do I fix this? Pretty much every electronic part on this motor including the wiring harness has been replaced in the last three seasons. Motor runs perfect other than this. Thanks!