I normally use Organ size 12. I'm not sure that a size 14 would make that big of a difference, however.
Do you have another foot pedal you could try using? Or maybe a friend with a BabyLock pedal you could borrow? I had almost the same issue last week with my Brother. It would stop sewing completely and I'd have to turn it off, then turn it back on again. Someone told me it might be the pedal. Fortunately, I have 2 Brothers and the pedals are interchangeable, so I tried that and the machine worked perfectly!! I think my old foot pedal simply got gummed up with hair and lint.