3.0 merc riser gasket question

[Bootstraps]

1994 alpha 1 gen 2, 3 liter, Can anyone tell me why the rider gasket blocks off one of the passages? The blocked one seems to be a water port. When I opened it up, the old gasket failed over the blocked port, just curious whats the reason for that port, if you are just going to seal it with gasket material?

 

[achris]

You need to tell us a bit more about the engine. Merc have been using the 3 litre since 1968, and there has been many many :facepalm: different exhaust manifolds and elbows on them....

Serial number please.

Chris........

 

[Bootstraps]

You need to tell us a bit more about the engine. Merc have been using the 3 litre since 1968, and there has been many many :facepalm: different exhaust manifolds and elbows on them....
.

Woops! I got a little ahead of myself. I edited the post. It’s a 1994 3.0 alpha one gen II. I can get the #sn when I go down to the marina later.