singer 416?

hi have retimed my machine and adjusted needle postion it then sewed a couple of stitches then stopped stitching or picking up bottom thread adjusted bobbin holder and tried again now will not sew and stitch at all or pick up from bobbin put new needle and thread and spool and still no joy can anybody help have tried all things in service manual except looking at bevel gear as i would have to remove stitch mecanisam and don,t want to remove unless it is absolutley necessary
thanks
sue banks