How do I set up my Janome 1600p-qc for free motion quilting?

Adjust the tension the same way as sewing regular projects. You want the top and bobbin threads to meet in the middle of the quilt sandwich. When quilting, I use a lighter weight thread so I have a separate bobbin case whose tension has been tightened specifically for quilting. For other sewing projects using a standard thread weight, I use a bobbin case that is factory set and then adjust the top thread tension for each project.

Be sure to use a darning foot (or free motion quilting foot).
Use a brand new sharp needle, ie top stitch, embroidery, or microtex work well.
Check that the thread, needle, and fabric are compatible--Caution, the needle eye should be the right size for the thread weight.
AVOID old or bargain bin thread!
Be sure to drop or cover the feed dogs.
If your machine has it, use the needle down feature.
You may need to adjust the tension for FMQ--I have to tighten the bobbin tension a little to keep the bobbin thread below the quilt surface (so I bought a special bobbin case and set the tension for FMQ and that's all I use it for.)

Lots of web sites that talk about how to free motion quilt. Then, it's PRACTICE, PRACTICE, PRACTICE! I use a portable white board and draw free motion designs on it (while watching TV, etc.). The idea is to get it fluid without jerking, jumping, speeding up or slowing down, etc. When your hand and brain are able to work smoothly, then you can probably do free motion quilting. Practice on scraps of fabric and batting (preferably the same kind you will be working on). Cut up some 14 inch squares of fabric and batting and draw designs on them and see if you can stitch them. Some advice: don't watch the needle...look at where you are going in front of the needle. Don't expect perfection to happen overnight. Many quilters have been FMQing for years and still make mistakes. (I've made a few quilts and my stuff still looks less than professional, but it's all mine!)

Free Motion Quilting with Janome 1600P sewing discussion topic...

All About Needles

You need to drop the feed dogs, install a darning or free motion quilting foot (make sure the presser foot is lowered). Because you will not be using the machine to move the fabric, the stitch length selection is of no importance. Make sure the stitch width is set to zero. You should test FMQ on a scrap quilt sandwich of the same makeup of your project, ie quilt fabric with batting sandwiched between. The upper tension should be set so that both threads meet in the middle of the quilt sandwich. Because it is FMQ, some extra adjustment may be needed.

Once the tension is where you want it, you can practice FMQ until you can move it smoothly in conjunction with the machine speed.

Practicing on a white board with erasable markers is a handy way to learn to move smoothly. The most difficult part of free motion quilting is learning to move the fabric smoothly. Do NOT lack for practice as that is the only way to improve. Those people who make it look simple have been doing it for years!

How to Free Motion Quilt on Regular Sewing Machine

Free Motion Quilting for Beginners Part 1 Video from Sewing with Nancy

Free Motion Quilting

Learn How to Free Motion Quilt Stippling

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Is it a new needle? a dull needle or one with a burr on it can cause those problems that you mention.The kind of needle you use is also very important. I like to use a 70/10 or 80/12 jeans needle depending on how thick the thread is.

The needle HLX5 is proper for the 1600P, if it is a 1600 PDB the the DB x K5Q1is the correct needle. Normally a size 14 or 16 is good for quilting.

Doug

Please ensure that you are uing the correct size needle for your that you are using. are you using a straight stitch needle plate. Please let me know what size thread and needle you are using

I recently purchased a Janome 1600P-DB and in order to do free motion quilting I had to cover the feed dogs with an index card. I also cut a small section out of the card to allow for the thread and needle to move freely. Standard tape was used.

Try practicing on a test piece before moving on to the quilt. Batik fabric is beautiful! I would check the thread size and needle. I tried quilting with invisible thread and had the same problem. The minute I changed to 50 wt.thread and a new needle the problem disappeared. I've found that 40 or 50 wt. thread works best on my Janome.

Try a different thread. It may be old or dry. Even some new threads seem to be finicky.

am I right that the feed dogs do not drop on this machine?

Yes, this is correct....but you have to change the needle plate to a thicker one, so the feed dogs will be below the needle plate.