Welcome to the board! I'm sure you'll find your way around with all this good advice.
Bobbin tension is a tricky thing. Many people will NEVER touch that little screw on the bobbin case. But it's not so hard to find out if there is a problem there.
Take your bobbin case out with a bobbin of thread in it. hold it up by the thread. With a little jerk, the bobbin should lower a little and then stop. If it won't lower at all with a small jerk, then the screw is too tight. Loosen it just a little, not an eighth of a turn. If it lowers and won't stop, the screw if too loose. Tighten it just a little and try again. Sometimes the tiniest amount of turning that screw will make a big difference. Keep working until you can hang onto the thread, give a little jerk and the bobbin lowers a few inches and stops. Then it's perfect.

Along with getting your machine "tuned", make sure the top and bottom threads (100% cotton) are from the same spool of thread. My 11 year old Janome works with any thread, but my husky 857Q only works with 100% cotton.
Let us know how you progress.

I just wanted to tell you that all this advice is right on and I can't add anymore to it. And NEVER be afraid to ask a question here! Everyone on this board is so helpful!

You should check Leah Day's class on Craftsy - Free Motion Quilting A Sampler - or at least her website-FreeMotionProject.com. She is great at FM quilting and her class was very informative and fun. You can also see some of her designs on youtube - just search for Leah Day. good luck and your older machine can handle it just fine!!

Don't ever be embarrassed to ask a question, only to remain in ignorance.....welcome to QB, the place to find good ideas and great people.

I'm no expert, but have FMQ both on my cheapie Brother from Wallyworld and my fancy Elna. Besides dropping the feeddogs, and using a darning foot, the only thing I do with tension is loosen the top stitch (thread) just a tad so it doesn't pull on the curves. several of the comments already given are important--new needle, clean machine (a tiny ball of lint can cause problems with the bobbin), and ALWAYS bring the bobbin thread up to the top of the fabric before you start the FMQ! Other than that practice,practice, practice! And drawing out your designs on whiteboard or paper really does help get that muscle memory. Check out some of the tutorials on the web for some ideas beyond stippling, too.

Thanks everyone. Yes, I always use a new needle for most garment projects and did same when doing the quilting. I used a 90/14 with 100% cotton: same spool for needle and bobbin. I did the jiggly thing with the bobbin and it didn't move at all so I loosened the screw titch by titch until I had the bobbin dropping just an inch or so. Made quite a difference when I sewed some practice swatches (just material pieces, no batting)...much happier with the stitches. I then did as you suggested and "went up and down" my needle tension dial and found the spot where I was most happy with the result. Then, I put my presser foot pressure back to its normal setting. Next, I made some practice swatches with some leftover batting, on with the darning foot and down with the dogs and off I went......
Practice swatches weren't too bad for a beginner...quite happy with them. So now that I have the Janome back to "normal" I figure any further problems I have are going to be "me" not the machine. I'm thinking that perhaps I should buy a really cheap poly filled quilt from Kmart or such and practice FMQ on that? That way I'm getting used to moving bulk and weight around?? This could be the last piece in the puzzle??
And no, I wouldn't buy a new machine just for FM stuff......just thought I would spoil myself next time my better half buys another motorbike!!

Welcome from another Aussie. If I spend some time doing a practice piece and use the man on a galloping horse technique I'm okay but it won't win me any prizes. I usually only do stippling on small projects.

I was so happy I was able to give directions good enough to help someone. :o
I've been fixing my bobbin case tension for years, mainly because I sometimes do bobbin work. I put light weight yarn on the bobbin and invisible thread on the top, so the bobbin tension needs to be changed for that, and then put back.

Lots of great advice here! Good luck finding the solution. Don't get frustrated, just keep at it, and you'll find what works for your machine.