Issues with Janome 9102D Serger

I have a quick question for you all regarding the serger that my wife and I picked up.

It's a Janome 9102D serger that we got for a really good deal at Hancock Fabrics.   The reviews that I read on it were fairly positive. 

But I'm having an issue with the lower looper.  The thread and I don't know how to explain this except that it is pulling out of the hole in the lower looper. 

It will do like 10-20 4 thread overlock stitches and then the lower looper thread just seems to "come out" of the hole at the tip of the looper piece and there goes any type of an overlock. 

I rethread it and it will work for a while and then it will do it again.  Is it the thread we are using being too tight, too loose or is it the machine itself you think?

Sounds like a tension issue to me. Do you have a manual for this serger?
I would try looking up tension issues and how to adjust. If you manual comes with photos or illustrations of correct/incorrect stitches, you might want to study these carefully and compare your stitches. You can then make the adjustments recommended by the manual advises.

I completely rethreaded it last night.  (I'm getting pretty good at that even with my ape like digits.)

That seemed to fix the problem. I called Janome tech-support after I did that and they said that it could possibly have been something to do with the loopers being threaded while in the wrong position. I didn't quite understand it, but all I know is that it's working again.

Thanks for the help Irene!