Mercury - Premium Gear Lube 80W-90 Outboards & Sterndrives Marine Formula 858007K01. Overview. There is a quiet confidence that comes when you know your gear is ready for anything the water throws your way. That's what Mercury's Premium Gear Lube 80W-90 delivers - steady, reliable protection that doesn't quit, even when the weather turns and the waves start to talk back. Whether you're cruising along the shoreline or running wide open across open water, you'll feel the difference in every smooth