So I adjust the valves and bent the stop on the throttle control plate. That seems to do the trick. With the exception of the up and down reving. At about medium idle, it lopes like it's got a huge cam in it, and will die. But at high idle, it revs up & down. At high throttle and the deck engaged, it runs a lot better. So correct me if I'm wrong, I'm thinking I got a bad carburetor.
BTW, thanks for all your replies. I'm a dummy at this stuff, I know it. But being a trucker for 15 years, and no longer able to do so (because of my knee), trying to fix small engines is some sort of income. I usually don't have this much trouble. This one has been a real nightmare.