1996 Mariner 75HP leaks oil from oil injection tank when tilted up

[wtromb]

Has there been a mod by Mercury to prevent these engines from leaking oil out of the oil injection tank when tilted up?

 

[Captain Mustard]

I'm also interested to hear if anyone has any answer.
I made sure my cap gasket was good (replaced it), but it seems the hole in the top of the cap still lets oil out.
I've been not filling it up all the way so I don't make a mess :/