Your bobbin case is commonly known as Appolo and is an absolute pain, the design was changed many years ago but I have people sending me pictures of the bobbin case area where the machines have not been converted, the bobbin case should sit completely flat on the raceway, if the thread is bunching up it could be not enough gap between the bobbin case and the right hand silver part of the guide, push the bobbin case to the right with your thumb and look at the gap, there should be enough room only for a thread thickness of about number 40 to pass through, if it is too wide it will pull the bobbin case up and jam all the thread, there are two screws on the right hand side that you can slacken off to adjust the gap.
drivewithken@blueyonder.co.uk
Ken
drivewithken@blueyonder.co.uk, January 2008