cooling plate

I live in South Florida and took my boat out for it first run since purchasing in March. Ocean water temperature was around 80 Deg. When running my Bilge pump I noticed the water coming out was very hot (Almost burning my hand) Could this hot water be caused by the cooling plate which is...

I purchased an 04’ GTX from a guy who left it in the water and unfortunately it’s calcified so bad that it needed to be taken apart to clean up. I have everything ready to go back together but I'd like to know if there are any specific guidelines to re-installing and re-sealing the riding plate...