Hi Dick. Just a small suggestion. I remember having a similar problem. I loosened up the set screws on a large pulley and no go. So my solution was to get a large pulley puller. Oh man it was tough going getting it of the shaft. When I finally got it off the shaft had two furrows in it. Somebody way back must have had a loosening problem and put in backup setscrews over the original ones. I had one of those forehead slapping moments. I now remove the sets all the way and look at whats in the hole. Take a look.
Peace and good luck.
Phredd