Jcpenney 6401 sewing machine

Your machine is an older mechanical. It needs cleaning and oiling to keep it going. It is probably seizing because the old oil has dried. Continued use could damage the motor.

Wheel on right side that controls the needle up and down is very tight...

ok. Never pull fabric, it will bend the needle and cause you even more problem. So stop doing that.

Look in your manual for where the feed dog switch is. It might be under the "darning" area.

Good luck

Your machine isn't threaded correctly... or the needle isn't the right size, or the top tension is too loose.

Check under your needle plate for a build up of bits of thread. Look for the tiny wick under the bobbin in the race area... give it 1 (one) drop of oil. Make sure you needle isn't bent and is fully seated.

have you checked the presser foot to see if the presser foot is holding
the fabric against the feed dogs so they can move the fabric thru to
be sewn by the needle?

the feed dogs are what move the fabric thru the machine to sew it
if the feed dogs are not working, then they need to be checked
to see if they have some loose or broken or need to be retimed

when the fabric does not move then the feed dogs under the needle plate need to be checked to see if there up or down.
if the feed dogs are down then the lever or switch needs to be pushed up into the correct position
if the feed dogs are up & they are not moving the fabric like there suppose to, cause it's there job to move the fabric against the presser foot,, then they need to be check

the gears that do the zig zag stitches should be checked to make sure there not worn & weather they might need be be greased

in the needle plate area you'll find the feed dogs, they move the fabric forward as you sew, they should be up to sew . most sewing machine have a lever or knob that can be moved to change the feed dog position, unless then knob is broken

I'm a bit confused, this isn't a serger machine as far as I can see. So do you mean an overcasting foot where you sew a XXXXX type stitch along the edge of the fabric? The overcasting foot just helps you to line up the fabric edge and sew over it neatly.

if you go to this page http://www.sewingpartsonline.com/necchi-6022-sewing-machine-parts.aspx
there is an instruction manual for sale.

http://sewmamasew.com/blog2/2009/06/feet-feet-feet/ is also a great resouce on sewing machine feet with good photos of what they are used for.

Here is a video of overcasting foot in action http://www.sewingmachine-sales.co.uk/sewing_machine_info/video/34/adjustable-overcast-foot.html

If you are wanting to sew knit fabric then you just need to use a small zig zag stitch and a ball point needle to put elasticity into the seam. Or your model may have a stretch stitch, where the fabric is moved forwards and backwards during the stitch formation to add some elasticity.

Sewing elastic stretched onto fabric is a bit different with a SM, can be fiddly and hard to keep everything lined up nicely and stretched. Some machines have a little device which clips onto the needle plate in front of the needle that you can feed elastic through and tighten it to tension it, then just use a three step zig zag stitch to seam over this onto your fabric. But I don't know if Necchi has such a thing, your needle plate would need holes in front for it to clip into. Elna had these on their swiss machines in the 80's but haven't seen a similar device for a while.

Hope I've answered your question and not completely misunderstood your problem. Purchasing a manual is often the best way forward when a machine is unfamilar. Or www.sewing.about.com is great resource.

If the loops are forming on the bottom it is the TOP thread tension you need to check. Make sure it isn't too loose. Also is the needle the right type and size for the fabric? Check the stitch out on plain cotton fabric if a tension adjustment doesn't fix it.

The TOP thread effects the UNDERSIDE of the stitch and the BOBBIN thread effects the TOPSIDE of the stitch :)