I've only had trouble when it was batik top and backing. It definitely helps to wash the back. I didn't adjust tension but with batiks the needle holes don't close up as fast so it looks worse than it actually is because you see the hole and you also may see the thread poking up which may lead you to think you are flatlining when you are not. I adjust so I like the top stitches and run my fingernail on the bobbin stitching. If it doesn't catch I continue. I also would use a new needle and you may want to go up a size as well if you are having trouble.