I purchased a Janome 423s to use here as I have a Janome 6600 in Australia.
I have had issues since I purchased it... Took it to the local repair man,
it has come back and the bottom thread runs along the bottom of the material(if you pull the thread it just pulls out) It shouldn't do that should it ?

Also when I sew a fancy stitch with a different colour thread in the top (blue thread) and the bobbin (grey thread) it comes out blue thread on the top and blue thread on the bottom.Should it do this or should it be grey on the back..Think I am having a senior moment as I use to do alot of sewing but life has gotten in the way the last couple of years.
Thanks for any help as I have no one to ask here..

well it sounds like the top tension is set way too low, try moving to a higher number and stitch again, keep moving a little at a time untill it gets even , not sure I understand the other question

your tension is off, try turning the tension knob just a little bit, like 1/4th turn at a time and sew a little bit to check until the stitches look the same on the top and on the bottom...the bobbin thread should not be able to be pulled out at the end of a seam. there should be no sign on top thread on the bottom or bottom thread on the top when your tension is set correctly. good luck, it sucks to have to deal with tension issues!

mine will do this if the plastic bobbin has a burr on the side of it. It doesn't allow the machine to make a correct stitch.

If you bought it from a Janome dealer, you should take it back to your Janome dealer and let them get it straightened out?

Thank you for the suggestions ..Yes tension issue do suck.:).I was getting so frustrated. It seems it was the thread I was using on the bobbin , as well as needing to turn up the tension a bit . Tried to do the right thing and had the same brand top and bottom .as they say you should...
Re bobbin burr funny thing that did happen the other day..

Appreciate your input....