Mercury - Premium Gear Lube 80W-90 Marine Lubricant For Outboards & Sterndrives 8 oz Tube 802844K01. Overview. Your outboard's gearcase takes the most punishment on the water - protect it with Mercury Marine 802844K01 Premium Gear Lube. Specially formulated for outboards up to 75HP, this 80W-90 gear lube delivers superior protection against corrosion, wear, and moisture damage. It's made specifically for marine environments, with additives that keep gears coated and lubricated even when water en