Old, old old omc stringer water pumps!

[Ron342]

Hello Seacraft folks - hope there's some OMC Stringer guys here! I have a SC 20' 1972 with an OMC stringer 2.5 outdrive I'm trying to get back in the water. Never worked on stringers before but have the factory manual. I need to replace the water pump and casing and have it down that far - ie - the 4 big ss bolts are out of the bottom of the upper gearcase, the big ss flange is off, the pump housing is tapped out and loose in the bottom of the gearcase housing (which looks like it was freeze cracked just above the pump casing at some point - but not the pump casing) so the ss pump top plate is loose as is the pump casing but the shaft seems to be stuck in the spline above it - which if I'm seeing the diagram right is just a slip in fit with maybe an oring. I've tapped it some but no go.
Is there something I'm missing or are my eyes just tired!!
Thanks
Ron