Mercury - Oil Tank for Select Diesel and TwoStroke Outboards Oil System Components Durable Marine Polymer 8M0064075. Overview. Anyone who has spent long days on the water knows that trust in your engine is built on the small things - the parts you rarely think about but rely on every mile. An oil tank is one of those quiet essentials. When it's working as it should, you feel that reassurance in the smoothness of your throttle, the steadiness of your idle, and the confidence that your engine is b