1997 merecury force 120 shift shaft spins freely

[brendanmcd37]

hey guys, brand new to the forums. i recently just inherited a 1987 suntracker bass buggy pontoon through a recent family member passing, it has a 1997 mercury force 120 2 stroke on the back.i got it running and took it out on its first maiden voyage earlier this week, and found as soon as you start the engine, its in forward gear and driving, no neutral or reverse. when you put it into reverse, it drives forward faster.i know absolutly zero history on this boat/motor and have no prior knowledge as to whats been done it it before. after doing some reading on the forums it sounded like this was a fairly common problem and that all i would have to do is take the lower leg off, and put some pliers on the shift shaft and spin it to forward detent, and then install the leg with controls in forward gear. after taking the lower leg off last night, the shift shaft spins freely, with zero resistance, doesnt matter what direction i turn it, it just spins and spins. so i popped the bushing/keeper that holds the shift shaft down off, and pulled the shift shaft out to see what i can see down there and im not to totally sure what i should be looking at down there, but what i beleive to be is the cam doesnt feel like it has any splines left in it. with a very long screw driver feeling the edges in the cam where the splines should be, i can feel slight bumps and roughness but no splines. splines on the shift shaft look completly fine. the bolts holding the leg on had antisieze on them and werent all that tight, and by looks of the impeller it is new-ish, im assuming when it was put back together last whenever the impeller was done, it wasnt assembled properly and its ran this way for some time now. what should my plan of attach be for getting this old girl back together properly here? im new to fixing boats, but i have a mechanics background and am not scared to tackle anything, just looking for some advice on where to go from here now. thanks guys, hope this wasnt to long and drawn out