Mercury 110 9.8 reverse lock won't engage

[@ReelChris]

I did a search but couldn't find anything on this specific topic.

I'm working on a 1973 Merc 110 9.8 that shifts gears fine but the reverse lock won't engage when shifting. I can manually manipulate the link rod to get the the lock to engage and disengage. It's worked in the past and then suddenly stopped. My understanding is that there's a cam in the lower unit that should push the link rod but I took the lower off and don't see one. I've found this parts diagram for the very similar 1975 model, but they're not very enlightening:

https://www.crowleymarine.com/mercury-outboard/parts/466_14.cfm

https://www.crowleymarine.com/mercury-outboard/parts/466_16.cfm

Can anyone offer assistance on what needs to be adjusted or replaced to fix this?

Thanks!

 

[@ReelChris]

To update this, the link rod, #18 in the attached picture, actuates the reverse lock if I manually move it up and down. The link passes through the bottom of the driveshaft housing, but terminates in a flat nub that isn't connected to anything. If I pull it up, I can pull it out entirely. I thought I could get a better look at it what it should be attached to by removing the outer cover of the driveshaft housing (part number 13 in the picture), but that would require removal of the reverse lock mechanism and the clamp assembly. I wasn't up for that much work to satisfy a hunch.