Put a new needle in- if a needle is even a bit worn for some machines it won't sew correctly. Try a Schmetz universal needle. The rule of thumb on a needle placement is the flatside points away from the bobbin. So with this machine if the bobbin is to the left of the needle the flat of the needle shank should be to the right.
You'll also notice the little finger at the top of the bobbin. In this case the bobbin thread has to also go up between those little pinching fingers though the tip. The point of the finger on the bobbin should be straight up when loaded and the bobin has to sit securely the race way. This is one of the more complex bobbins to load. Take a look around the internet for a free downloadable manual to also help you keep the machine running in top condition. We have several of these in our inventory for refurbishing which I have managed so far to avoid.