Kenmore Sewing Machine Stitch Length Problem Repairs
If your vintage Kenmore sewing machine is having problems with stitch length, stretch stitches, or reverse stitches, this post will include videos, photos, and tutorials, for troubleshooting, and fixing stitch length problems.
Feed Dogs not feeding correctly, is one term people use, to describe this problem, and while it can be caused by dirty, linty feed dogs, that need cleaned, and oiled, the actual issue inside the sewing machine, often is caused by the pivoting reverse cam follower, not being able to pivot fully. This part, and the tilt of it, controls both forward, and reverse stitch length.
The fix, is usually to remove the old sticky oil, usually easy to do with Qtips, dental swabs, or a long narrow paintbrush, dipped in rubbing alcohol, or unscented kerosene) and then oiled, one or two drops, with sewing machine oil, or Tri Flow oil.
Basically, you are using the alcohol, or unscented kerosene, as a solvent, remove dry sticky oil, that turned into a lacquer, or glue. The oil is your lubricant, to allow metal parts to slide against each other, without sticking.
Kenmore stitch length mechanism, inside the machine, is combined with the reverse, because they are all part of the controls (basically the stitch length cam) for stitch forward and reverse movement. This is a pivoting part, and if it can't pivot fully, your machine won't be able to sew all of the forward and reverse stitch lengths, which it is engineered to sew.
This video is my attempt to help illustrate how this mechanism should work, and why. Depending on which model you have, your mechanisms may vary somewhat, but the same principles apply. The degree of tilt, and pivot, determines how far your feed dogs travel, and move your fabric.
Sometimes, your stitch length knob may become frozen, or the stitch lenth doesn't change, when you turn the knob. If you have freed up the pivoting reverse cam follower, and it pivots fully, check behind your stitch length knob, to determine if it has a retractable rod, or piston, which has become stuck, so it can't retract, or extend, as far as it should, or if it isn't able to spin, because of dry sticky oil (some models have a very long, stitch length rod, which actually needs to pivot, in the back wall of the machine, sometimes, a white plastic cap, covers where you need to clean and oil, to fix those models).
If the stitch length rod is not retracting, and extending, clean and oil the area the rod is supposed to move in and out, behind the knob. You may need to remove the side panel of your machine, to access this area. While you are in there, it is a great time to clean, and oil all parts in this area, and check your machines belts, to make sure they are in good shape.
Models with bottom mounted motors, can be easier to access with both the motor removed from the motor mount (one nut to remove, leave motor wired), and laid on their back, with the side panel off.
This is a good time to oil the bottom pivot point, at the oil port, of your feed dog drive rod (for want of a better description), as well as all of the other oiling points, on the underside of your machine.
A dental mirror, and headlight, can help you see the mechanism behind the knob, and faceplate, better.
1703, 1803, 1603,
On rare occasions, you may need to resort to using a penetrant, like WD40, immediately followed by TriFlow oil, or sewing machine oil, to help get the oil sucked into the stuck area. Let it set a few hours, then test it. You need to flush out the WD40, (with compressed air, or extra oil) once the parts or freed up, or it can cause lint to adhere to it, and absorb moisture, as well as a waxy substance, in the WD40 can dry to a glue, sooner, rather than later. Do NOT just apply WD40 and assume it is a lubricant, use it only as a penetrating solvent, for best results.
Protect the motor from getting cleaners, or oil on it, while working in this area, behind the knobs and faceplate, if you have the bottom mounted motor.
