Where can I get info to adjust my bag stitching machine. its not sewing?

Question:I have a National portable bag closer that will not sew. It makes double and treble loops but does not interlock. It is a single thread machine.

Answers:
have you tried contacting the machine manufacturer ?
else, try a local sewing machine store that specializes in repairs - check the yellow pages ( http://yp.yahoo.com )