If the horsepower of your Mercury outboard lower unit is 75 and below, SAE 80W90 Gear Lube is recommended.
The 1973 model, 7.5 hp Mercury outboard, requires 6.8 oz. of gear oil.
For a 90hp Mercury two-stroke outboard, you should use a high-quality lower unit gear lube specifically designed for outboard motors. Mercury recommends using their own brand of gear lube, such as Mercury High-Performance Gear Lube or Quicksilver Gear Lube, which offer excellent protection against wear and corrosion. Always check the owner's manual for specific recommendations regarding viscosity and any additional requirements.
For a 2004 Mercury 115 outboard, you should use Mercury High Performance Gear Lube or a suitable equivalent that meets the manufacturer's specifications. Ensure the oil is specifically designed for marine lower units to provide optimal protection and performance. Check the owner's manual for any specific recommendations or requirements.
To rebuild a lower unit on a 40hp Mercury outboard, start by removing the lower unit from the engine by unscrewing the bolts and disconnecting the shift linkage. Drain the gear oil and disassemble the lower unit, noting the arrangement of parts. Replace worn components such as seals, bearings, and the water pump, then reassemble the unit, ensuring all parts are properly aligned. Finally, refill with the appropriate gear oil and reinstall the lower unit on the outboard.
For the 80 hp Mercury, you may use any brand of gear oil that has been blended for use as an outboard motor gear lube. There are many brands available other than oem, and are specially formulated for outboard use.
22.5 fluid ounces (or 666 ml's) per our 1994 Mercury 125 outboard manual.
The 5 hp Mercury outboard requires no special type gear oil. General recommendation is for a GL-5 class lubricant, i.e. hypoid 90w. Most any of the oem, or aftermarket gear lubes, manufactured for outboard use, will work just fine.
outboard motor will start and idle, but dies out under load
Using Valvoline 75W-90 synthetic oil in the lower unit of a Mercury outboard is generally not recommended unless it meets the manufacturer's specifications. Mercury typically specifies its own gear lube, often requiring a specific type such as Mercury High-Performance Gear Lube or a similar product. Always consult your owner's manual for the correct type of oil to ensure optimal performance and to maintain warranty coverage.
For a Mercury outboard motor's lower unit, it's essential to use a high-quality marine gear oil specifically designed for outboard motors, such as Mercury High-Performance Gear Lube or an equivalent. These lubricants offer excellent protection against corrosion, water intrusion, and wear under high-stress conditions. Always check the owner's manual for the specific type and viscosity recommended for your particular model.
motor shuts off when put in gear sometimes