TGood

I recently purchased a $5.00 Auto Reel from an online auction complete with accessories, manual, etc. After cleaning it. It sewed very nicely. In fact, it sewed a nicer seam using a walking foot on some stage curtains we were making than a couple thousand dollar Bernina with a walking foot!! However, when I went to sew with it the other day, it slowed to a snails pace. I am wondering... what is the problem? Could you machine specialists help me toubleshoot? Motor? Foot control?

Thanks for whatever help you may have to offer!
T