It does on my Brother/BL machines. I have to thread with presser foot in the up position. Check your manual for threading position to see if there is mention about it.

The check spring (shaped wire) on the tension is supposed to prevent things like the thread jumping out of the take-up. Maybe the check spring got damaged?

I have had a similar problem on my Janome. What I discovered after I removed the front plate to take a look was a 2" piece of thread was broken off in the threading track. As soon as I removed this little piece of thread I was back in business with perfect stitching and no more choking.

If the pressure foot is down then the tension is engaged. I was taught to always thread with the foot up.

I have the same Janome. This is an excellent idea. Take your bobbin out and thoroughly dust everything in there.

It must be something with the Janome machines. Mine is the MC6500 Professional and it does the same thing. Can't tell you how often I've had to stop and rethread the machine. Sometimes I feel like just giving it a "time-out" and walking away from my project. I use a big cone thread and the stand alone thread holder, maybe it's the thread itself? I use Craftsy 50 wt. thread.

I also have a Janome 6600. Mine does the same thing from time to time. I use cones of thread and also spools. It doesn't seem to matter. Clean the bobbin case and check for little pieces of thread. Try switching to a different brand of thread? There seems to be no rhyme or reason why my machine does it. I emailed Janome that is what they told me. If you look on the internet Janomes do this sometimes.

I have two 6600’s, one in Arizona and one in Oregon. The one in Arizona started doing the same thing and I could hardly wait to get back to Oregon and sew without a problem. Guess what? I’m back in Oregon and that machine is doing the same thing! Go figure. Thanks for all of your comments.

Check all of your thread guides, sometimes lint or thread does get stuck. Also threading from the opposite direction will keep your thread in the take up lever. You should always thread any machine with the pressure foot up. No tension pressure, so your thread goes into every guide it is intended to go into. Best wishes.....Love my Janomes....they did discover years ago that this was a problem for their machines, they, then starting putting a "lock" on the take up lever. Duh moment, why don't they test their machines with real sewists before releasing a machine for market.....amazing.

I know this is old, but how do you thread the take up lever from left to right? I am not understanding this suggestion that has been given in a few places... Thank.