Kurt, It could be a variety of things causing your High Idle situation. Things to check for are:
1. Check the spring. It should have no tension on it with trottle lever all the way forward to idle.
2. Check all linkages for binding at different throttle positions.
3. Check the bearing for play. Make sure the outer ring on the bearing is not "wobbling" over the balls.
4. Loosen the throttle shaft housing at the connecting rod housing end and use a large screw driver to "raise" up on the front end of that throttle shaft housing. If the tractor idles down, you have a linkage adjustment problem or excessive wear in the bushings.
Good luck and keep us posted.//FB