I have twin 1997 Merc 150 EFI's.
Problem #1
Starboard engine lower unit oil is milky-brown.
I can pump in about 28 ozs. of replacement gear lube oil.
Problem #2
Port lower unit oil is black & has burnt smell.
Also, can only pump in 4-5 ozs. before it flows out top screw.
All 4 washers are new...