I just took a look at a Merc 6 (Of course same as the Nissan & Tomatsu) and noticed that the zinc is a TINY little square on the side of the lower unit. It look about 1" square.
Has anyone had a problem with them eroding really fast? It seems like it is about 1/4 the size of the one on the Yahama... seems like it would go really fast?
What have you seen?
On edit; Did find some discussion on OB motor zinc's here. Nothing addressing the little zinc on these motors though....