Old Spirit motor with stuck shaft

[Rusty Driveshaft]

I just bought an old spirit motor and it's is in unbelievable shape and running condition, The only thing is, is that when I started it up it wasn't pumping water. Therefore i realized the water pump was gone. I did manage to get the lower leg off and striped everything else off nut the shaft is stuck in the crank and I have tried endlessly to remove it but it's seems impossible. I want to know if there is some sort of pin holding it in place inside the motor or if it's just corrosion and I can do something else to free it from the crank. If anybody has any advise at all i would greatly appreciate it. Thanks