Since you describe it as very little tension I assume you get loops on the under side of the fabric? Because you have lots of layers and batting you can try a larger size needle and as Cari mentions, sharp tip. I would try something like 100/16 or 110/18 and if the stitching improves it is the layers of fabric needing a sturdier needle to pull and tighten up the stitch. The larger neelde leaves more room for the thread. I have to admit I have had little to no trouble with universal needles.
If the dial turns and you can notice gradual tension increasing from 0-9 (pulling the tread throught the needle and back), it's probably fine. Having the throat plate off and on again is easy, and so is cleaning around the feed dogs. My first time having the tensioner appart took me a quite a while and lots of fuzz watching tutorials on the web and struggeling with how to get it back on right. It's one of those things that get easier once you have done it a couple of times.
Last edited by Mickey2; 10-20-2017 at 04:07 AM.