Well, I cleaned the dust from the bobbin case, and did a re-think as to the kind of thread I am using. It's ordinary Connecting Threads brand. I put some Mettler that is made for that, (40wt) AND just for good measure put the machine at its slowest speed. It is doing better. Guess it does not like Connecting anymore for satin stitch. It still works great for regular sewing though.
The foot for this machine is marked J. The manual says that is the one. So I guess I will go buy some more Mettler. :-)