1991 omc 115 hp water pump replacement

i read allot of posts on this subject and its clear there are diffent desigs for the gear shift linkage aand i still have issues...the question ie does the horizontal shift shaft have to come all the way out or just travel about a half an inch to the port side to relase the vertical shift shaft? i had the coter pin actually it was a hitch pin...pulled that out but i also see the bolt on the port side that obj described ...i cant get the arm that goes on the stbd side of the shaft off and and the shaft only only slides about a half an inch to port until the arm butts up against the housing...i dont see any thing else holding this arm on the shaft and dont understand what the hitch pin is there for if not to hold an inner shaft to an outer one