Could anyone tell me how to get more out of the tension adjustment on my Juki mo-735 coverstitch looper? I have it set on “H” and I would like it to be just a smidge tighter. If I turn the dial past the “H”, on the opposite side of the “H-M-L” there is an arrow, but I’m not sure if this has any function whatsoever (see photo).

Neither the user manual, the service manual, nor online videos address my issue. There are no Juki retail stores in my part of the world, or even independent repair shops who know anything about cover stitch machines. (I know this because I paid $125 to have it timed, but the guy only tightened screws and made the problems worse).

This combo coverstitch/serger mechanism is typical of some other models of Juki, Bernette, and possibly other brands of coverstitch machines.