Singer 15-91 Reverse stitches are a mess.
 

The forward stitches are great, when in reverse it actually looks like I have no tension or very little.
I have googled and did a search here, the only suggestion I read was adjust the pressure of the pressure foot, which I tried to no avail.
Help with this problem would be greatly appreciated.
Thanks so much! Jo Anne

Tension can be a fuzz to get right, and it's all about cleaning, getting the adjustment right. Don't give up on this, and don't assume it's done until you have done a bit of test sewing and fine tuning along the way.

General way about it; set top tension dial in an inbetween position; between 4 and 5. Thread the machine up with a basic sew all weight thread, a good quality mercerized cotton or Gütermann sew-all polyester are up to the standard. You know the thread is not causing the problem. Do the drop test on the bobbin case; then take two layers of shirt weight cotton fabric or quilting type cotton and fine tune until the stitch is balanced.

Other things to check that can mess up:

Match needle size and thread weight well, too small needle for the thread can cause trouble. Good quality needles are a must, most brands are luckily. Check for needle in the correct way.

Take the top tensioner appart and clean them. It can be full of lint, a piece of thread caught between the disks. Make sure the dialed knob turns freely from about 0 -9 with out hault. Check the spring on the bobbin case too.

Take the throat plate off, thoroughly clean the feed dogs; scrape all grooves and corners clean with a tooth pick. In theory it shouldn't affect tension, but if there's a lot of lent in the bobbin - feed dog are it will.

Make sure the bobbin case is clean, as mentioned behind the tension spring as well. Make sure the thread is properly behind the spring.

This is a very trouble free model this way, and I'm sure it's one of the basic things that needs to be sorted out.

Are the feed dogs lowered? There is a thumb screw on the underside that adjusts the feed dog.

I have an 80/12, new, Universal Schmeltz needle in, was using two layers cheaper fabric and 2 layers of flannel and a 2 fabric batting combo., Guterman 100% cotton thread, brushed the area where bobbin is and the feed dog.
The machine has sat for almost 3 yrs.(my bad) I did oil every spot, (had manual with me), ran floss thru the tension discs.
Have the upper tension between 4-5, bobbin thread and spool thread are the same. have threaded and re-threaded several times. double checked bobbin and bobbin case is very clean.
This was not an issue when I last used the machine.
Have not taken the throat plate off yet. The dial knob does not turn that freely. I am not having to force either.
Pennycandy: yes feed dogs are up. The forward stitch looks great(front and back) the mess, tension issues are in the reverse stitch.
All go thru the checklist with the machine in the AM. Be a first to take apart the top tensioner, I'll save that for last.
Thank you Ladies!!

With that many layers you really should be using a sharp needle. A universal needle isn't quite sharp, isn't quite ball point so it's universally good for nothing. Go back through and oil the machine well again paying attention to the making sure the stitch length lever moves freely but not loosely and stays still when you put it in reverse. Run it in for a few minutes to let the oil get in where it's supposed to go. Try some test stitching. Does the bad reverse stitching happen at the beginning of sewing or at the end of the seam? I'd be more inclined to think it's a feed dog issue.

Cari

Since you describe it as very little tension I assume you get loops on the under side of the fabric? Because you have lots of layers and batting you can try a larger size needle and as Cari mentions, sharp tip. I would try something like 100/16 or 110/18 and if the stitching improves it is the layers of fabric needing a sturdier needle to pull and tighten up the stitch. The larger neelde leaves more room for the thread. I have to admit I have had little to no trouble with universal needles.

If the dial turns and you can notice gradual tension increasing from 0-9 (pulling the tread throught the needle and back), it's probably fine. Having the throat plate off and on again is easy, and so is cleaning around the feed dogs. My first time having the tensioner appart took me a quite a while and lots of fuzz watching tutorials on the web and struggeling with how to get it back on right. It's one of those things that get easier once you have done it a couple of times.

Sorry! I should have been more clear on the fabrics I was using. Either 2 layers 100% cotton fabric, or 2 layers of flannel or fabric-batting-fabric, using scraps. I am going to go swap the needle right now and check under the plate.

Mickey2: I reread your comments and a little light bulb went off, the loops are on top-so we have bobbin issues! Yes! the thread was out of the slot, is it possible when I took a brush to the feed dogs and went under the plate could that I bumped the bobbin thread enough to have jump the slot?
I changed to a 90/14 "quilting" needle
Reverse stitches have vastly improved!
What I am seeing now is puckering of the fabric when in reverse only? Is this normal or to be expect?

Unfortunately I was unable to remove the plate, the screws are not even budging.
Can you over oil? My drops were rather big when I oiled yesterday. Would it be a good idea to oil again today? Taking into consideration the machine sat for almost 3 yrs.

Cari-in-Oly- Think I'll find a place to donate any and all universal needles! Thinking the Universals came with the Bernina in a cabinet I bought last year. I normally buy, Quilting, Microtex, Jeans, needles and aim for 80/12 per my Pfaff service person.
Thank you all for your assistance! QB members are the best!!