Something similar happened to me when I was about 12, My mother said I couldn't use the SM until it was oiled. Soooo I proceeded got the manual out n read, removed all "dust bunny's/felt like rugs from under the feed dog plate and oiled anything that moved. Gears looked a little dry so dad gave me some grease he used for farm implements. When MOM got home she about had kittens. I didn't know any better AND I WANTED TO SEW. The next time she used the SM it worked better than ever. She forgave me. We continued to use tractor grease on that old machine until she traded it for a T&S.