JLII0SE sewing machine

SOURCE: Brother XL-5130 Sewing Machine

Put the thread through one of the holes. Then put the bobbin on the spindle. Pull about 3 or 4 inches out of the hole and hold on to it. Start winding the bobbin. After about ten turns, or when the winding thread is secure, you can stop the machine and cut off this 3 or 4 inch tail. To insure that the thread winds up and down the bobbin and not off the top or bottom, there is probably a metal bobbin tension disk that the thread must pass around before it goes to the bobbin. It is probably on the left of the machine and may or may not be part of a thread guide. The thread must pass around this disk on its way to the bobbin in order to put tension on the thread so it will wind properly. If you can't find the disk, which is a small metal button or screw with some type of somewhat moveable spring cap, you can just get the thread to pass through your thumb and forefinger. Hold your hand 6 or 8 inches to the left of the bobbin and pass the thread between your thumb and forefinger so that it makes the thread go in a direct straight line to the bobbin. Pinch the thread only enough to keep it taught but not tight and let it flow through your finger to the bobbin. The thread should go up and down evenly on the bobbin. If not, move your hand up or down to position it so the thread will wind up and down smoothly. It will not be necessary to move your hand once you find the correct position needed for winding.

SOURCE: Kenmore Sewing Machine model # c877.15

I have an old Kenmore and here are the directions from my manual: 1. Draw thread from spool through bobbin winder tension discs. 2. Wind thread around an empty bobbin several times. 3. Place bobbin onto bobbin winder shaft with thread coming from rear of bobbin. Push bobbin winder latch against bobbin until it clicks. 4. Release clutch by turning clutch knob toward you. Start machine.

SOURCE: Bobbin thread breaks

Things to check for thread breakage (top or bottom)

1. Good thread in the machine - not hand thread, cheap thread, quilting thread.
2. A burr on the hook - a small nick on the hook can grab and tear threads, however this usually causes the top thread to tear, not the bottom
3. Make sure a new needle is in the machine - one made for the material you are sewing
4. The bobbin must be installed to rotate in the correct direction in your bobbin case
5. And I'll say it anyway - tensions - the primary cause of thread breaking - Remember, there are TWO tensions in a sewing machine, top and bottom. Also, the thread you see on the bottom of the stitch is the top thread, and vice-versa.

SOURCE: Brother Sewing Machine model:CS8150 bobbin thread problems

The top of the machine is not threaded correctly. First raise the presserfot then rethread the machine. Bottom looping is usually caused by a lack of top tension. There could allso be a bur on the hook.

SOURCE: I have a Brother SE-270D

its the problem of the timing belt in your machine its extra loosen or extra tightned or is slightly came out of its position or finally broken.
as the machine is proper just missing the proper speed as it should be .
it is running continuosly as you stated.
check the timing belt and make it proper if its worn out and needs replacement this is how its done

There is an adjusting screw on the right side of the machine head. Follow the motor bracket to the machine head and loosen that big old screw or bolt which will raise or lower the motor giving you slack to remove or replace the belt.

feel free for further queries
thanks