Hi,I havent asked a question in quite a while.I have a 206 R consew.I oiled it good,took the belts off,left the top off,and the front cover so I can see what my problem is.There is no thread on the machine.I have a monster wheel on it.Iam turning the wheel in the right direction.and it goes smoothly for awhile and then I hear a thunk and it stops..I can back up for a couple of inches and it goes smooth a gain.Can you help?thanks,old navy