Hello, I have a Kenmore wich is made by Janome. I also have had that happen on my machine. The bobbin as you said did help me also. But I did discover my tension has to be in the neighborhood of 2 for freemotion quilting. It doesn't say that in my book but I will get the loops and the railroad tracks if it isn't on the 2. This may not help, hope it does I know how agravating that is.