1989 Merc 70 check valve

[Starcraft94]

When I was running motor in the yard I noticed a small valve leaking oil blow the carbs but on the block. I check online and it’s labeled check valve. No hose was loose or evident. Is it just for testing?
not sure. Don’t want to cap till I know and or run a tube but can’t find where the other end would be.

 

[The Force power]

Mercs. had on the two-strokes a check-valve at the bottom main-bearing area to drain the not used up / burnt oil in the premix & push it up through a tube/hose to the top main-bearing for lubrication & to burn-off.

In the pic. I can't really see if that the one I'm referring to