If you look closely you will notice ME references two different #40 part numbers. I don’t remember why, but I do remember they are different in gate. The release rod #37 hooks to lever #21. Unless you have the motor hanging in the air it can be difficult maneuvering in those tight spaces. Those gates on the side are tilt locks ONLY! Not for trailing! They are usually bent, broken, or just all out of whack if they have been used to hold the motor up while trailering down the road. The engine ultimately jumps up & down till it beats the brackets to death.
The lock mechanisms work similar to small motors. Just a latch that hooks over the thrust rod. The lever pulls the rod which raises the latch up. Of course you have springs, etc. Look like most of the stuff is still available, but you could spend some money putting it all back original if it’s been beat up. Most have by now.

Dan in TN

I could be wrong, but I don’t remember the tilt locks dropping in place on their own. Not to say they don’t.

The release rod has a bend at the bottom that simply hooks into a hole in the hold-down latch. The upper lever is on a shaft with a release lever on the front. It is very common for it to be broken off. It gets broken by hitting a submerged object at speed.