If I ever had the opportunity to have a discussion with a Mercury engineer about their decision to run salt water through cast iron, then I would give them an earful of feedback.
My exhaust parts would last three to four years, I would then discard / replace those obscenely expensive parts using OEM Mercruiser parts and the clock to failure would start all over again.
Years ago I redesigned my exhaust system, from salt water sitting in cast iron 24/7/365, with NO way to drain, NO way to flush, to flush with fresh water, soapy water, Salt Away, then drained bone dry after each usage.
The parts still look brand new.
Prior to this change I would split the gasket seam every year to gauge if the parts were still good. Now they always look good.
