What does this little guy do? It was blocked off with a rubber cap, but the cap has dry rotted and come off. Is there anyway to get rid of that fitting? It is in the way from getting the carb perfectly level on the motor because that fitting when it has the rubber cap on it hits the mounting bolt for the rubber carb flange.

Isn't that the where the drain tube goes? Mine has a drain tube going thru to the top of my lower unit. On mine its facing down but I assume its on a vertical PD motor?

I would assume its a vacuum port for some other application. You could pull the brass nipple out and plug it with small pipe plug, set screw, or just cut it off and silicone it. I left mine there and just siliconed it.

It's a vaccum port. You can just plug it or remove it and seal hole.