Oh boy, another gasket sealer question. Almost as much fun as oil and Ethanol questions. Let me say one thing first. Evolution happens.
For years, OMC put most gaskets in dry. But that was before OMC invented their Gasket Sealer product. Actually they borrowed Mercury’s Perfect Seal #4. Anyhoo, those copper fire rings were state of the art back when. But I am here to testify they caused electrolysis in salt water. My own personal 1958 Super Sea Horse 35 died after only 4 years in salt water due to the aluminum eaten away at the cylinder/head gasket area. I bought that motor new and it had never been overheated, nor had the head been removed. Eventually, OMC smartened up and started making the fire rings from aluminum, but not all models at the same time
Back to the sealer question. As I mentioned, OMC put them in dry and didn’t even mention the subject in their service manuals. However, posted below, is a page from 1972-18hp Evinrude manual. It clearly says to use OMC Gasket Sealer on the head gasket. Now we all know the 1972-22 cubic inch 18hp motors weren’t that much different than the 1957-18’s So why the difference? Evolution. Or maybe they saw too many motors like my 1958 SSH.
Also, along about that time, OMC came out with gaskets made from a different material and also with aluminum fire rings. They were first used on big motors, such as the V-4’s, and were a direct replacement for previous gaskets Those new gaskets were factory coated with a sealer and were plainly marked DO NOT USE SEALER. They also issued a service bulletin on the subject, which I still have if I were to spend an hour looking for it. Evolution.
Let the opinions continue.
