Ron, does it start at high speed the minute you plug it in?  If so, that's the governor resistor that's shot.  This part is pretty easy to replace, but not so easy to find...  They do show up on eBay from time to time.  There used to be a repair person (Dave's Repair in Pennsylvania) who did all kinds of Mixmaster repairs and sold parts, but last I heard, he was winding his business down.  But you never know, he may still have the part!