100% Gasoline vs 10% Ethanol

I loaned my mower to my brother, 22hp Kawasaki Cub Cadet. I filled it up on the way home and called me after a couple of days to ask if it had always been hard to start. He brought it back a few days later with a full tank ans he was right. It was a pain to start. Had to choke it hot or cold and it seemed to spin for ever before starting so I thought tune up time. I ordered parts for tune up and before I got them the grass needed cutting so I filled it back up with pure gas and it starts instantly again. Haven't tuned it up yet.
No more corn in my mower!