sounds like an issue with either how the needle is threaded, how the needle is inserted in the shank, or how the bobbin is place in the bobbin case.

you might want to: insert brand new needle, make certain it has the 'flat' side of the needle correctly placed; then re-thread the machine, following the instructions exactly; remove the bobbin and re-insert exactly as listed.

Carolyn

Thank you for your response. I started over from the beginning according to the instructions in the manual. I used the same needle, but made sure it was properly oriented. I redid the bobbin, as well. It still knotted up. When I got it untangled, it looked like the top and bottom threads were twisted around each other.

An update: I decided to narrow things down by applying basic troubleshooting procedures. The thread that I was using is a heavy grade that was recommended for my project. The needle that I'm using was installed by the lady who sold me the machine because it's the heaviest gauge of the ones that came with it. I tried using a spool of regular thread, and it worked. I switched back to the heavy stuff, and it fouled. The bobbin is loaded with the heavy stuff. Does this mean that a bigger needle will solve the problem?

In my experience as an amateur seamster, your problem is with tension. Heavy thread needs heavier tension than light thread. Try adjusting the tension in both places (bobbin and top thread) till it takes a reasonably good pull on both to make it go. Then test, adjust tension, and test again till you get the right stitch. Make sure the top thread tension and the bobbin tension are the same. This is a matter of feeling it out, since the top tension is numbered, and the bobbin tension is tightening a screw on the bobbin housing.

I agree with hobi, Relatively sure your tension needs adjusting and if there is a needle recommended for the fabric you're using you might need to change that too. Get some scrap pieces of the fabric you're using and start by adjusting the top tension 'til the top stitch looks the way it should. Then adjust the bobbin tension by tightening the screw a little at a time until the thread no longer balls up. Continue until the bottom and top threads "lock" in the middle of the fabric. (you won't be able to see the bottom thread on the top of the fabric or the top thread on the bottom)

Because I am still a beginner, I'll recommend to you what was recommended to me.

It can be difficult to correctly adjust the bobbin thread tension, although, in time, it can become familiar and easy to adjust.

For now, you can use heavy thread up top and regular thread in the bobbin. This way, you only need to adjust the top thread tension.

And, if I'm wrong and you are familiar with adjusting the bobbin thread, "sorry"!!! I'm just too much of a newbie to try that kind of thing :)

But, I have used two different weight threads on top and bottom and it worked well for me.

Good luck!

J.