Mercury – Quicksilver 85W-90 Extreme Performance Gear Lube, 1 Gallon | Gearcase Lubrication | 92-8M0111679

Overview

High-performance gearcases don’t get an easy life. Long wide-open runs, heavy loads, sudden throttle changes—those gears see everything. When you’re running equipment that hard, ordinary gear oil just doesn’t cut it. This Quicksilver 85W-90 blend is the stuff mechanics use when they know a gearcase is going to be punished. It hangs onto the teeth, stays thick when the drive gets hot, and gives you a cushion of protection even if water sneaks its way inside. If you want your lower unit to hold up to real use, this is the kind of oil you run.

Key Features

 • Built for High-Load Gearcases – Ideal for outboard and sterndrive setups that get pushed hard.
 • 85W-90 Weight – Holds up when gears are under heavy pressure and rising temps.
 • Tackifiers & Pressure Additives – Help the oil cling to gear surfaces instead of washing off.
 • Heat-Resistant Formula – Doesn’t thin out during long, hot runs.
 • Water-Handling Emulsifiers – Offers protection if water finds its way into the housing.

Engine & Boat Compatibility

 • Outboard racing lower units
 • Sterndrive performance gearcases
 • High-load marine and powersports gear systems
 • Performance-tuned applications

Performance & Practical Benefits

This lube keeps the gears feeling smooth and controlled even when the engine is working hard. You’ll notice fewer hot-run noises, better gear engagement, and more consistent performance on long WOT stretches. The oil’s film strength helps prevent metal-on-metal contact during sudden throttle hits—something that can take out a gearset fast. And if the housing picks up a bit of water, this blend buys you time until you can drain and refill.

Why Buy OEM

Mercury tests this oil in the same style gearcases it’s meant to protect—real heat, real torque, real load. It’s blended for the materials and clearances Mercury uses in their drives. Cheaper aftermarket oils might meet basic specs, but they rarely hold up when the gearcase is pushed to its limits. With something as expensive as a lower unit, OEM protection is worth it.

FAQ

Q1: How often should this gear lube be changed?
A: Once a season or every 100 hours—whichever comes first.

Q2: Is this oil only for racing engines?
A: No. It’s great for any boat that’s run hard or sees a lot of heavy use.

Q3: Will it help if water gets inside the gearcase?
A: Yes—the emulsifiers protect metal surfaces until you can service it.

Q4: Does this lube handle high-RPM heat well?
A: Very well—that’s exactly what it’s designed for.

Q5: Should I mix it with other gear oils?
A: It’s best not to. Drain completely and stick with one type for reliable protection.