I have a 362 which is basically this machine, but it has the stopmatic feature. It FMQs beautifully. It sounds like you have a thread jammed somewhere. If you were able to do it great with a top and then not, 'something' happened. You need to look closely with a flashlight, if need be. Look carefully around the hook area to make sure there's not a thread wound around the hook race and take off the top of the machine and look down into it and see if there are any threads stuck anywhere.
When did you last clean, de-lint and oil it?