Just put the 15-91 in an old bedraggled case, threaded it up, plugged it in and ................. I'll be darned if it doesn't sew. Dirty, rusty bobbin case, rusted needle, filthy everywhere and the thing sews. Mater of fact the tension is all but perfect. The more I mess with these old machines the more they amaze me.
This one will be interesting when I get the potted motor rewired and back on it. I'm wondering if the potted motor will turn it as fast as the external motor does?
Joe