My 15-91 started skipping stitches a few days ago. I checked the threading, changed the needle, checked the bobbin. Still no luck. So I attempted to remove the tensioner and got it totally messed up. Now it is going to the "hospital" today so that the "doctor" can fix it next week. Thank goodness I have a 201 (Moe) to use while Curly is gone. I could use my 66 (Larry) but I need to find some other feet for him.