aq125 cooling problem

Ran the boat in shallow muddy water and picked up debris in the cooling system lake water side. cleaned it all out and in the process had to replace the raw water strainer housing which cracked UGH. But that brand new housing leaks where it mates to the metal cover on the heat exchanger. I don't remember there being any gasket in between the plastic black strainer housing and the red metal heat exchanger (the one with the fins). The strainer housing is tight to the metal cover- should there be some gasket material in there? Not inside the strainer housing I mean between the bottom of that housing and the exchanger itself? Ive had this system apart in the past and looked at all the drawings in the manuals and online and don't see a gasket material there, but it seems like there should be something. Thanks.

here is a pic of the old parts but new part is the black strainer housing that sits on top of the heat exchanger. disregard the rtv gasket material on the old one. i cleaned all of that off before installing the new strainer housing.

While I am not familiar this motor or its cooling system, I did some minor research > looked at what a new strainer looks like and tired to figure out how its all assembled. It appears that the plastic strainer sits on the heat exchanger and is held down by those two toe clamps. And it looks like a flat surface to flat surface type of mating. And in all the pics I looked at I did not see any gasket material. I find this odd, and hope someone with experience on these systems pipes in.

In the meantime, here is my suggestion assuming flat to flat mating:

With the new strainer ensure the mating surface is flat and free of any mold lines. Get some fine emery cloth of 400 grit. Place it on a nice flat surface, a piece of glass is best if you have access to it. Wet it and with a nice even pressure on the strainer pushing down on the emery cloth move it around, back and fotth and in circles. Stop often and look at the mating surface > does the entire surface look like it just got sanded? Keep going if not. Idea here is to get the same surface finish on the entire mating surface > this way you know its flat. 400 grit will not take much material off, idea is to just kiss it if you follow my meaning.

Next cut a piece of the 400 in a circle such that it matches the strainer diameter of the surface you just polished. Use double sided sticky tape, like for a carpet and carefully apply it to the rim of the strainer’s matting surface. The key here is to NOT have any bumps or folds in that tape > needs to be nice and flat. One way to do that is to apply the pieces of tape radially out. See mockup below. Now stick that round piece of emery cloth to it. You now have a “tool” to polish the heat exchanger (HE) where it mates with the strainer. Put it on wet and twist back and forth. Look at the HE mating surface. Does is look nice and even? If not, keep going until you have that nice even finish.

Clean it all up and reassemble > does it leak? If yes, pull apart and dry it all off again and apply a thin layer of RTV sealant to the mating surface of the strainer and reassemble.

Good luck and keep posting your questions and results.

AS I examined the old strainer housing today, I saw that there was an old rubber sealing ring inside of the plastic housing. I don't know if I replaced a new ring on the inside of the new plastic housing. I will take that new one off the heat exchanger and examine it, and that should be the sealing ring that prevents water from leaking out between the housing and the metal top of the heat exchanger. I will let you know.
Joe