Mercury - Oil Filter Element Engine Protection 35-8M0066483. Overview. This little filter ends up doing a lot of the dirty work for the engine. After a few long days on the water, oil starts picking up all kinds of fine grit, and this element is what keeps that junk from circulating. It's a quick swap-nothing complicated-and feels solid enough that you don't worry about it once it's in place. It's the kind of part you change without thinking, but the motor always runs better when you keep up wit