1983 MCM 260R T-Stat Housing Questions

[San_Diego_SeaRay]

I have a 1982 Sea Ray 270 w twin MCM 260Rs that I'm fixing up. Needed to replace the thermostat so bought all the gaskets and stuff. But I don't want to get this wrong was hoping I could get some input in the proper assembly of t-stat hosing. First of all, I'm working off the following exploded diagram from THIS website:

And the website indicates that part number 27-41812 is the correct gasket, which I have:

But I also have another gasket that looks like it allows water to pass thru a passage right next to the t-stat:

Another issue is that the brass ring fitting is not flush with the housing, which will prevent the upper housing from sealing:

I've stacked the items exactly like in the exploded diagram, from bottom to top: T-stat, cork gasket, then the brass ring fitting (the turned in edge of the fitting is down; pressed against the cork gasket).

So I have two questions:

1. Am I OK using the gasket that is called for (part number 27-41812) and
2. what am I doing wrong where the fitting isn't flush w. the housing?

Thanks in advance!

 

[alldodge]

IMO you should use the 27-41812 gasket to seal off the passage.

Your cooling system needs to keep that sealed off to keep your block full. Your system is the one on the left pic below.


Now if you want to upgrade and go for newer style we could work on that

 

[San_Diego_SeaRay]

IMO you should use the 27-41812 gasket to seal off the passage.

Your cooling system needs to keep that sealed off to keep your block full. Your system is the one on the left pic below.

Now if you want to upgrade and go for newer style we could work on that

Thanks for the help.

I'm not going to "upgrade" at this point, but if I did in the future, what's involved? What are the benefits?

 

[alldodge]

Thanks for the help.

I'm not going to "upgrade" at this point, but if I did in the future, what's involved? What are the benefits?

Upgrading is fairly easy. Replace exhaust manifolds with ones which feed all water through the bottom of the manifold. Either have gaskets to flow water into the exhaust elbows or get the dry type (better) which feeds water from manifold to elbow via a hose or separate passage. Then in stall thermostat housing like the one in the link below
http://www.mercruiserparts.com/Show...r=2333&bnbr=140&bdesc=STANDARD+COOLING+SYSTEM

Probably need a couple hoses

 

[San_Diego_SeaRay]

Excellent. Thanks again!