path49 good advice the needle type makes all the difference in the world and a minor tweak then is all that is needed. Also watch the width of your twin needles since they come in different widths, to large for the machine and you break em.

Looking at the 2mm twin needles I have here, 4mm is a relatively wide twin. I agree with the moving of the needle if the Elnita can do it. Watch which way the hook grabs the thread from and move the needle a little closer to that side but be careful not to move so far that you hit the needle plate.

An entry level machine like most of the Elnitas I've come across may have enough of a timing "error" built in from the zig zag alone as to be intolerant of a large width twin needle. If none of the other suggestions work - try (if the project will allow it) a slightly narrower gap and see if that helps.

Also, tension can affect the ability to make a stitch. Too loose and the thread occasionally flops on the wrong side of the hook tip. Too tight and it's too tight against the needle still when the hook tip comes around. Unfortunately, sometimes tension has to be played with at the same time as a skipping problem. The newer embroidery machines seem to be quite prone to this and checking their timing is fun when there's so much lash in the hook mechanism that it's close to 1/8" "slop".

My 1973 Elna 62C uses a needle with a single shaft and two needles. The intake side of the tension has just one opening, but there is a separator on the left side as the thread exits the tension. I have misplaced my instruction book, but this way works well for me. She threads from front to back. Size 11 Schmertz Universal is this machine's needle of choice. She won't sew with a Singer or off brand needle.

Irishrose2, we noticed the single opening on the tension, but I'm mystified by the separator you mention. Can you possibly describe it in more detail or post a picture? Or, I wonder if this is something your Elna has but our Elnita does not?

We did have a size 11 needle, but it was for stretch knits (which we were trying to sew). Thank you for your input!
Best,