I am currently working on setting up link/sync and timing myself. And have been running into similar issues. (I posted a thread couple days ago describing my issue)
Is the throttle lever supposed to contact the engine block as a hard-stop for its upper limit when going WOT with the throttle? It doesn't appear so in the pictures shown. If not, then what stops the throttle lever and keeps the butterfly valve in the carb from going past horizontal?
When I set mine up so that the cam follower comes off of the cam between the two marks, nothing stops the throttle from advancing once my carb is open so it wants to keep going past "WOT" position and binds the throttle rod/linkage as I turn the throttle.
Regarding the timing advance stop setting, mine seems similar to what the other guy mentioned, roughly 1/2" or so of threads sticking out past the lock nut. I attempted to verify this on the water last night, and was close within a couple degrees. You can imagine the "fun" we had with my brother running the boat WOT while I'm also in the back trying to get a timing light on the flywheel. lol. Good times.
I know this is an old thread, just trying to gather some information. Cheers.