by Dave
(Wisconsin)
Hi all! Fresh water boat. Light coating Whitish foam on top right spark plug.pulled water jacket cover it was crusty white and grainy. Pulled off cylinder head and found small amount of whitish foam in top of head. I think the gasket is ok. The metal rings were unbroken or cracked. The cylinder walls look really good. The cylinder gasket surface was 50/50. Meaning the inner 50% was shiny and smooth. The outer 50% was rough. Im not sure if that was a gasket compound or mineral buildup. My plans are to regasket after flat sanding the gasket surfaces smooth. And recheck for foam on the plug. A mecury mech said its getting in through the exhaust perhaps. He wasnt very optimistic. If I find foam again he said check the exhaust manifold gasket. One more thing. Im pretty sure there wasn't any water in my gas tank. It was drained and cleaned last season and its stored indoors. Any thoughts?