1979 merc 50 cooling problem

Hi all I'm hoping y'all can shAre some insight, 1979 mercury 50hp 4cyl, I just replaced the water pump a few days ago and when I ran the motor with the muffs there was only a slight flow thru the pisser, I have since blown air and water back thru the pisser to back flush and I'm getting plenty of water thru the prop and almost none thru the water pipe , I did run the boat this morning and it was producing a large amount of steam thru the square ports on the back of the motor, here are a few pics I took to show where the water is coming from

If you can see the cylindrical shaped part at the top of the next picture, water is coming out from in that area, it's to the left in the picture

And where all the steam was coming from

Thank you for any and all help in advance