Here's the tutorial that taught me how to service a motor. It's not hard.
http://mckennalinn.com/sewing-machin...g-a-motor.html
Also, if you bring the take up lever to the top or just over the top of its travel when you finish a seam, it will be easier to pull the thread and remove the fabric, AND it should start the next seam without balking. The take up lever right at that point is finished with the stitch and going to begin the next.
Cari