Elna 745 Stitches

With my favourite overlocker not working I have been using my Elna 745.....We didn't get off to a very good start...... it looks like the knife needs sharpening....The Elna 745 was very temperamental when I tried to do a four thread stitch (it looks more like a three thread to me). Is that anything new, we have a love hate relationship! I finally figured out how to get an acceptable stitch I altered the blade width and the she started to behave herself...Here is a pic of the stitch.

This just doesn't look like a 4 thread to me....
But all 4 threads were moving, so it's got to be???
Anyway it was the best she would do on the day....
I think she needs a service.... better wait till the other one is back