Originally Posted by
NapaJohn
My first guess would be that there is gunk under the bobbin case causing it to not spin freely creating the nests.
I second this. Also, Miriam's right in that it can also be the tension discs. When you buy a new machine, you should always clean the tension discs and the bobbin area anyway. The former is extremely easy and taking the discs apart is not difficult either.
Simple test for the top tension: crank (top toward you) until the needle is on its way up. Make sure the foot is down, turn the tension dial to zero and try pulling at the thread: It should come through easily. Now repeat at 3 or 4. If there's no difference and you can still pull it through easily, your problem lies in the top tensioner. At about 3 or 4 it should bend the needle (don't pull it hard or you'll break the needle). If the top tensioner is OK, the bobbin area is likely to be the cause.
Note the position of the tensioner on the threaded part before taking it apart (take a photograph). I put it on zero first.
The bobbin area: You have a URL for it above, and once you remove the feed dog, remove the locking ring for the bobbin then the other plate (next to FD) which holds the locking ring in position and lift out the bobbin case. I've done it twice in the past few days and there has been a large amount of thread and lint underneath each time. When the thread wraps around the case, most people (the previous owner of your machine, for example) just break the thread and keep sewing, so the amount of garbage is no surprise. I've only ever come across a clean bobbin area once: The machine had been serviced then immediately stored.