Elna Serger 624: front feed dog not pulling the fabric through, though it is moving.

Fabric jamming in your machine may be caused by the feed dogs. The feed dogs are those tiny teeth along the sewing machine underneath the presser foot as those teeth pull the fabric through when the needle is making stitches. Lint or debris in the feed dog area can jam the mechanisms preventing them to move.

https://sewingmadesimple.net/why-does-my-sewing-machine-keep-jamming/

Sounds like the small plastic cog/gears have slipped, this rarely happens and usually is from pulling heavier fabric through the machine while trying to sew. The teeth on the feed dog grips to a portion of the fabric and is tugged out of the track of the path of the rotation...
Not necessarily an out of timing issue if they are rotating independently, but likely will take a tech to disassemble it and replace the part(s). They likely will need to be replace rather than just placing them back into place.

Hope the response is helpful..

The needle never moves forward/back on its own for most sewing machines. The needle bar goes up and down. The fabric moves due to the action of the feed dogs. First remove the fabric from under the presser foot. Check for tangled thread wrapped around the feed dogs or fabric/thread going down into the bobbin area in a tangle. Next check if the feed dogs are up. (When the feed dogs are down or covered (on some machines), the machine is in darning mode. The fabric will only move if you move it yourself.) With the fabric out of the way, rotate the hand wheel and check if the feed dogs are moving. Open up the bobbin compartment and clean out any lint, thread or other debris that may be tangling the mechanism. Take off the throat plate and check the feed dogs. A damaged throat plate can stop the feed dogs from moving properly. You may need to replace the throat plate.

For some machines, you may need to make sure that the unit is not in bobbin wind mode. This is usually obvious since the needle bar won't move either.

I hope this helps.

Cindy Wells

Have you got a tangle under your fabric? If so, release the fabric and rethread your machine, making sure the foot is up during threading. Otherwise check the feed dog under the foot. There's usually a switch somewhere that brings the feed dog up or down. If it's down the fabric won't feed. Another point, what type of fabric are you sewing. If it's leather or leatherette you'll need to use a roller foot. Hope this helps.

Are the feed dogs actually raising, moving, and dropping (raise the presser foot and hand-rotate the handwheel and watch how the feed dogs are moving)? If not, check to see if the stitch length is set well above the zero (which means it sews in place)? Perhaps the presser foot pressure is set too firm and is preventing the fabric from moving under the foot.

Lower the front feed dog

Be sure you have the stitch length set high enough that the fabric will actually move instead of sewing mostly in one spot.

One other thing to check is the presser foot applying enough pressure to the fabric so that the feed dogs can grab the fabric? On the top left side of the machine, there is probably either a dial or a push-type button. That would most likely be the pressure adjustment. The tighter that is set, the harder the pressure the presser foot will apply and the more the feed dogs will grab the fabric.

Check that the feed dogs are in the "up" position so they will pull the fabric through the machine. Are the feed dogs actually moving forward, raising above the needle plate, pulling toward the back of the machine, and then dropping below the needleplate before moving forward again? If not, then the problem could be with the feed dogs.

Your machine appears to be a mechanical model. If so, it could be the machine needs a good over-all cleaning and oiling--a couple drops of fresh, good quality sewing machine oil every place that metal rubs on metal (no plastic parts, belts...). Feed dogs are frequently affected when the sewing machine does not receive regular maintenance.

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Is the feed dog raised into sewing position and not dropped as for darning? Feed dogs need to be in the raised position in order to pull the fabric through the machine.

If the stitch length is set too short, it will cause the fabric to barely move thereby causing the machine to stitch in one place.

Raise your presser foot and gently rotate the handwheel and watch the feed dogs. Do they rise when coming to the front of the machine, move toward the back of the machine, drop down below the needle plate, and move forward to the front of the machine again? If so, the feed dogs are working properly.

If the feed dogs never rise, they are in the dropped position for darning or free motion quilting when you would move the fabric manually.

If, on the other hand, the feed dogs do not move at all, then they are seized and you should probably get your machine serviced.

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Check that the stitch length is set to make ~10 stitches per inch. This stitch is long enough to actually move the fabric. If the stitch length is set too short, the fabric will stay barely move and the needle will stitch almost in place.

Check that the feed dogs have not been dropped for darning or free motion quilting. In this position, they do not rise and are, therefore, unable to contact the fabric to pull it through the machine.

With the presser foot raised and using no fabric, hand rotate the handwheel and watch if the feed dogs actually drop down below the needle plate, move toward the front of the machine, then rise above the needle plate, and move toward the back of the machine. If the feed dogs are moving in this manner, then they are functioning properly.

Is there lint or gunk stuck in the feed dogs? This will restrict the ability of the feed dogs to grip the fabric.

Are the feed dogs worn? Are the little teeth worn so there are no sharp points?

What type fabric are you using? If it is very light-weight or slick fabric, the feed dogs will have a difficult time gripping the fabric. Most machines have a presser foot pressure adjustment so that more pressure is applied between the presser foot and the feed dogs. Consult your Owner's Manual. The adjustment is usually a dial either on the left side of the machine, on the front of the machine located above the needle bar, or on vintage machines it is usually a skrew located under the top lid above the needle bar.

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the feed dogs need to be check, it's possible that they are broken.