80W-90 Hi-Performance Synthetic Blend Gear Lube, 32 oz Part # 18-9650-2

One quart fills the average 40-150 hp outboard lower unit with a little left over. Ideal for high-performance, heavy-load, or high-speed applications.

Why 10,000+ boaters upgrade to this synthetic blend

• Advanced synthetic formula – superior extreme-pressure protection for high-horsepower and racing lower units
• GL-5 rated – exceeds Mercury, Yamaha, and OMC high-performance specs
• Amber color – instantly spot water contamination or milkiness
• Reduces friction & heat – smoother shifts, runs 15–25 °F cooler under load
• Salt or fresh water – ultimate corrosion inhibitors, no seasonal change needed
• Meets/exceeds OEM warranty – perfect for Merc High Performance, Yamaha, BRP HPF Pro

Direct OEM Replacements

Full Specs

• Sierra Hi-Performance Synthetic Blend Marine Gear Lube
• 1 quart (32 oz / 946 ml) squeeze bottle
• SAE 80W-90
• API GL-5
• Amber color
• Synthetic blend for extreme pressure, high temps, and heavy loads
• Formulated for high-performance outboards, sterndrives, and inboards
• Works in place of all hypoid 90 high-performance applications
• Recommended pump: Sierra 18-9781 (sold separately)

60-Second Lower-Unit Oil Change

1. Tilt motor down, remove bottom drain screw.
2. Pump fresh lube in until it drips from the top vent.
3. Install vent screw FIRST, then drain screw.
4. Wipe, recycle old oil — done.

Free pump adapter with every 3 quarts

FAQs

Can I mix this with conventional gear lube? Yes short-term, but for max performance, drain fully and refill with this synthetic blend.

When to choose this over the Premium Blend (18-9600-2)? Use Hi-Performance for 150+ hp, towing, racing, or hot climates. Stick with Premium for standard recreational use.

Electric-shift or older OMC lower units? Avoid synthetics—use Sierra Type C (18-9620-2) instead.