cjr,
A couple questions if you don't mind.
First is your machine noisy? Ours makes an electronic hum as it starts and has a rattlely vibration at different speeds. Sounds like the motor. But I don't know.
I tried what you said after filling a bobbin, seemed to work a bit better. But as I tried to do back tacs and sometimes as I was sewing the thread would get caught twice around the bobbin carrier and jam the works up. I upped the top tension two numbers and seems to have cured that. Have you ever had that happen to you?
Basically the machine seems to be sewing good, no real problems but we have only been doing straight stitches so far.
Joe