My bobbin thread will not thread. When I bring the needle down, it comes up without the bobbin thread. The mechanism moves, but no thread. How do I fix this problem?

basically the problem comes from incorrect thread tensions
the main thread responsible is the needle thread as the tension is far too loose
tighten up that tension and it makes the needle on the up stroke pull the thread around the bobbin carrier and collects the bobbin thread and pulls it up to the material
with the needle thread too loose the needle thread is wrapped around the bobbin carrier again giving you the 3 threads ( 2 needle threads and 1 bobbin thread and the tangle jams the bobbin movement

1. REPLACE NEEDLE W/FLAT PART AWAY FROM YOU.
2. MAKE SURE THE TOP THREAD IS PROPERLY THREADED.
3. INSURE BOTTOM BOBBIN IS ROTATING RIGHT DIRECTION. (USUALLY COUNTERCLOCKWISE) ALLOW THREE INCHES OF THREAD PULLED AWAY.
4. HOLD TOP THREAD W/LEFT HAND AND ROTATE HAND WHEEL TOWARDS YOURSELF. DOES IT BRING THE BOBBIN THREAD UP?
5. IF THE BOBBIN CARRIER IS INSTALLED PROPERLY THE HOOK (POINTED OBJECT) UNDER THE BOBBIN SHOULD "HOOK" THE TOP THREAD AND BRING THE THREAD AROUND THE BOBBIN THREAD. THE NEEDLE AND TOP THREAD SHOULD BE PULLING THE BOBBIN THREAD UPWARDS. IF THE HOOK DIDN'T "HOOK" THE NEEDLE THREAD THE PROBLEM IS THE DISTANCE OF THE NEEDLE AND HOOK APART OR THE TIMING. YOU MAY TRY TO MOVE THE NEEDLE TO THE LEFT SIDE AND AGAIN TRY ROTATING THE HAND WHEEL. IF IT DOESN'T WORK THEN TRY TO MOVE THE NEEDLE ALL THE WAY TO THE RIGHT AND ROTATE THE HAND WHEEL. IF IT BRINGS THE BOBBIN THREAD UPWARDS IN EITHER CASE IT WILL SHOW A PROBLEM WITH TIMING. THIS WILL NEED TO BE ADJUSTED BY A PROFESSIONAL.
6. REMEMBER TO PUT ONE DROP OF OIL ON THE RACE TRACK BEFORE YOU PUT THE BOBBIN CARRIER IN.

Place bobbin correctly into machine.
Thread machine correctly.
Hold thread tail coming from needle in your left hand while moving the hand-wheel towards you so that needle goes down and then comes up all the way.
Pull up on the thread in your left hand and "voila!", the bobbin thread is up.

Bobbin is not moving, sounds like a broken gear, not a timing problem. Bring it in for service.

Check the needle to see if it is bent. If not then check the needle to hook timing. Turn the hand wheel until the needle is at it's lowest position. Start to bring the needle upward. As the needle gets to the edge of the hook/bobbin race the point of the hook should pass slightly above and behind the needle. If it isn't the timing is out. I would suggest bringing it to a trusted sewing machine repair person to reset the hook timing and check for any other damage.

try changing the needle
rethread the machine top & bobbin
make sure the bobbin is wound correctly & inserted correctly
into the bobbin case
if these suggestions don't help then you might think about having
the machine checked at a sewing machine shop

if im not mistaken, the bobbin when you place it in the bottom, you have to thread it is as well to the part where the needle comes down and collects and goes back up. please re-look at instructions for placement of bobbin

sounds like your keeping the upper thread too tight when you drop your needle down to catch the bobbin or the bobbin thread that you left hang out is too short, let me know if it works amy

From the Simplicity Sew Precious Model SWSP2 manual:

Inserting a new bobbin:

1. Place wound bobbin into the bobbin case.
2. Pull about 6 inches of thread out from the bobbin.

NOTE: Be sure that the bobbin rotates COUNTER-CLOCKWISE when thread is pulled.

1. Pass the thread from the bobbin, under the bobbin case spring, and toward the back of the machine.
2. Slide bobbin cover back into position.

Upper threading:

1. Turn the handwheel toward you to raise the take-up lever to its highest position.
2. Lower the presser foot.
3. Place a spool of thread and spool cap on the spool pin.
4. Place the thread into the first thread guide at the top of the machine.
5. Bring the thread down the right slot of the threading path, then around the tension dial. Push the thread tension release lever and pull the thread up so the thread is secure in the thread tension dial.
6. Bring the thread up the left slot of the threading path and through the take-up lever from right to left.
7. Bring the thread back down the left slot of the threading path and into the needle eye from front to back. (Clip the thread end with sharp scissors fro easier needle threading.)

Raising the bobbin thread

1. Make sure the presser foot lever is raised.
2. Hold the end of the needle thread with your left hand. Turn the hand wheel toward you with your right hand until the needle goes down once and comes back up, stopping when the needle is at its highest position.
3. Gently pull up on the needle thread. The bobbin thread, looped around the needle thread, will be drawn up through the needle hole.
4. Push the thread tension release lever and pull about six inches of both the upper and lower threads toward the back of the machine, placing them under the presser foot.

You can obtain a copy in pdf format for free at:
http://www.simplicityhomecare.com/ftp/whitepapers/SWSP2-english.pdf

The machine is relatively simple to thread. This is what I do and I've had no threading problems. 1. Put thread spool on the spool pin and put spool guard over spool pin to hold spool onto pin. 2. Take thread and put it under the bent tab by the circle tensioner. bring the thread around the right side of the circle tensioner and bring around the front of the circle tensioner thing back to the top hook on the far left side of the machine. 3. Take the thread around the backside of the top hook think until it threads through the flat piece on the left side of it. 4. Bring the thread down through the first (right side) channel and under the plastic piece to the second (left side) channel. 5. Bring the thread up the second channel and around the moving thread holder and past it's flat metal piece to hold it. 6. Tuck the thread around the small wire thread holder below the needle screw. This may take a few passes to catch it. 7. Thread the needle from the front and run the thread between the teeth of the presser foot. 8. Put a bobbin in the bobbin case so that the thread pulls off the bobbin from the left side of the bobbin if you look at it from above. 9. There is a small channel in the bobbin case that is covered by the bobbin tension flat piece. Pull the bobbin thread through this channel and into the empty space where the needle thread will catch. 10. Place the bobbin case into the machine with the little set bobbin arm pointed to the sky so that it fits into the machine without wiggling to the right or the left. 11. Turn the, uhhh brain fart, the hand wheel until the needle comes back up with the bobbin thread hooked over the needle thread. Take a narrow thing, like scissors or a seam ripper and pull both threads until the bobbin thread comes up. Now your machine is threaded. Use these directions with the pictures in the book to get this machine threaded.