If you have your feederhouse off of the combine, just leave that big pulley on the shaft.
Pull the pin on the left end and slide the shaft out with the pulley on it . It is good to keep that thing tight on the shaft like it come from the factory if you can.
Or take a short piece of heavy pipe big enough to slip over the shaft and key on the right hand side of the shaft, have someone hold a counterweight on th left end of the shaft, strike the pipe with a big hammer. That will sometimes move the hub backwards from the tapered keystock just enough to loosen it. And if that dont work ...., well the advice was free anyway.