Hi first time poster. I'll try to be as specific as possible. I had over heating issues. Replaced impeller, thermostat, plugs, wires, distributor cap. After replacing the distributor cap the over heating seemed to stop. However when I would put the boat on plane and the rpms were around 3500 I heard a slight ticking not knocking. I stopped driving it and when I got home I noticed that the oil was slightly chocolate color. Being the boat was used in salt water I removed the exhaust elbow to find the gasket blown out into the exhaust area near the only open water port. All other water ports were clogged. I cleaned all ports and checked for leakage with acetone. My question is could this be the reason for the chocolate looking oil? The oil level was not that high. Thank you in advance.