I just realized that these motors do not use head gaskets, rather gasket maker is put around the water orifices on the cylinder side. How do the cylinders create compression? Is it the flexible sleeve mated to the cylinder head which sets up the compression?
The 60 degree motors use a large O-ring instead of a head gasket to seal the cylinders. Not sure how OMC came up with that idea but it works. I pulled the heads on my 1998 Evinrude a few years ago to look into an overheat problem and the factory O-rings were still in good shape. I did replace them with new ones.
1954 Johnson CD-11
1956 Johnson RD-18
1958 Johnson QD-19
Yes, the orings are laid into a groove on the block, perhaps they are compressed to the point where they just look like part of the block…
And yes, the cylinder orings should be replaced every time the heads are removed. Use the sealer prescribed in the manual to avoid corrosion issues….