I had a starter fail on 25hp Kohler and when I took it apart the gear wouldn't slide on the armature shaft. I took it apart cleaned it all up and bearings looked good and bushes were okay so I put some lube on the shaft and it now works. The electrical shop wanted $140 to rebuild. Now I don't have any illusions that this thing will last very long so I got a new one in standby. But I am wondering what kind of lube could/should be put on that shaft. Most lubes will gum it up with dust and may actually hurt things?