On the intake manifold parts diagram, could that broken tube be Part 38 - a cut to length "house" (odd name) associated with the "air silencer"? If so, then according to the diagram, part 43, a nipple, looks like it's supposed to be on the end of the "house".
Nipple Part https://www.crowleymarine.com/parts/13037.cfm
What the "house" does and whether it is important to have a nipple on the end, I have no idea. Nor how long it should be per the meager instruction to "cut to length" that shows up when you click on 38 in the diagram.
EDIT to add: The marineengine.com website part listing says cut the "house" to 6.5 inches. Not clickable so scroll down to part 38.
I'd look at the Service Manual if you have one to see what it says about it.
EDIT #2 to add: only slightly less trustworthy than Wikipedia, I conducted a google search for johnson V4 air silencer. Despite the name, *I think* I gleaned that its function is in control of air flow to the carbs. That sounds important in ensuring you've got the correct air/fuel ratio to the carbs... hopefully persons with true knowledge will share.