Mickey2

The trick is to go through a list of check points, even two or three times. You will eventuall detect the problem.

Basic things;

Needle in flat side to the left, threads from right to left.

Take out the throat plate, bobbin case and bottom drip pan. Inspect hook, race and feed dog area carefully, there might be a piece of thread or broken off needle tip stuck some where. It's surpising how fast lint and fluff can gather on some types of thread.

Clean bobbin case, check for dust, grime, pieces of thread behind the tension spring. Check between the disks on the upper tensoner too.

I would assume needle bar height and timing is fine, it's not the most common problem on these; but while you have the throat plate off you can thread it, put the bobbin case in draw up the bobbin thread and see how the hook picks up the upper thread and loops around the bobbin thread. You can't really form stitches until you have the throat plate back on and a piece of fabric under the presser foot.

Since plates are off and all the cleaning is done you might as well oil and grease the lubrication points. I have even found pieces of thread and lint behind the face plate on some machines. Thorough cleaning and oiling will sort out a lot of issues, this model can be a bit tricky since it's very compact and have a few hard to reach places.

Another thing with the featherweight; always start with the needle down, hold the bobbin and upper thread on the first stitch; just pull them it lightly backwards to prevent them from getting dragged down before the first couple of stitches secures them. This is a common cause of thread mess on these.

To sum it up, in need of cleaning, caught piece of thread, and thread getting pulled down the needle hole are the most common causes of thread mess. If the machine is new to you, make sure all gears, hinges, joints and levers move freely, stuck or slugish parts it can cause all sort of diffuse problems.