Re: 1963 johnson 75 hp-lower end diagram
Remove the inspection plate on the side of the midsection, about half way down. Remove the second plate behind the first one. In there you will find the shift rod connector. Remove the lower screw from shift rod connector.
Remove the 8 bolts holding the lower unit to the extension if it is long shaft, otherwise the exhaust housing. Twist the lower unit back and forth slightly while pulling it down and away.
The water pump is right there on top of the gearcase as shown on the picture.