I had a similar problem of tangled thread -- the spool would twirl around several times with each stroke. I tried putting one of those crocheted "spool doilies" over the spindle under the spool and that created enough drag to keep the thread from unwinding too fast. Just a thought...
The featherweight shop sells them, but if you crochet, they are easy to make and there are lots of free patterns available for crocheted flowers.