Poppet valve/relief valve issues 1978 2.4l Merc

[rujr]

1978 2.4l Merc. Appears it was a salt water motor after pulling the T Stats and seeing the corrosion. Decided to rebuild the poppet as well. Ordered what I thought was the right poppet kit. Received the kit and nothing fits right or looks right. When I pulled the original poppet apart it had only a very thin piece of rubber, a metal washer, screwed to the normal plastic poppet valve. It has the same hard plastic and soft rubber gasket in the block as the new poppet kit. After further reading it seems the older 2.4s had what they call a relief valve, not a poppet valve. What kit or parts do I need to get this thing back to stock??? What is it supposed to look like??? It is frustrating that I know this motor runs well but I can't even start it because of the hole in the cooling system. Thanks for the help.

[rujr]

I answered my own question after looking at the parts diagrams. There are three different poppet designs. I have the earliest. They are all very different. I guess sticking with the original is best???

[rujr]

Is there anyone on this forum that can provide an explanation for the differences in Mercury poppet valve designs throughout the years. The early 2.4s had a "Relief" valve inside of a housing that is connected to the Starboard T stat housing (Poppet design #1). Then there is the progression to a single barrel plate "poppet" valve housing, without any connection to the T stat housing (Poppet design #2). Then there is the newest poppet valve which has a full cover like design #1 but still no connection to the T stat housing. Why are they entirely different? Is there something wrong with converting my older 2.4 to design #3? Just talking through it, I know the poppet valve stays closed at low RPM to maintain block temperature at efficient combustion levels. I know the poppet valve opens at high RPM to provide the full capacity of cooling to the outboard. The primary difference in poppet designs is where the water is routed I am thinking.