It is likely the machine is used for heavy stuff with heavy thread - that will change your tensions. You might get an extra bobbin case just for lighter weight thread then only have to adjust the top tension when you transition. Can you shoot a picture of the foot? If it is a straight foot it would quilt - you can reset the clutch so it goes slower at first. Use finer needles and thread then rework the tensions. A high shank darning foot or a commercial darning foot may fit it. If it is a dedicated walking foot you won't like free motion with that. If you are doing straight grid type quilting, you might like it if it is set up for it.