Sir, you need to be patient. I am working as fast as I can. I can only type so fast.
Plus, I have 2 dozen people on line from Florida, who have decided to wait until yesterday and today to try their gensets. They are all in a panic, and want an answer "right now". I can only do so much.
Friction and that clamp are all that hold the fan on, yes. But What happens is that rust builds up on the fan shaft, and causes the metal to swell. It also creates heat, which makes the plastic fan hub stick horribly.
As I said, I break as many fans as I don't.
One thing you can try, is use a deep well socket, or a piece of pipe, just big enough to fit over the shaft, and reach down to the fan hub. Smack it once or twice with a hammer (like you are trying to force it on further). It can break up some of the rust.