Mercury - High Performance 4-Stroke Marine Engine Oil Verado Series Synthetic Blend 8M0053664. Overview. There's a certain comfort in knowing your engine is protected by the same oil trusted by boaters who push their rigs hard-hour after hour, tide after tide. That's exactly what you get with the Quicksilver 25W-50 Synthetic Blend Marine Engine Oil 8M0053664. When you fire up your Mercury Verado or another high-performance four-stroke, you can feel the difference in how smoothly it settles into