The 1973 model, 7.5 hp Mercury outboard, requires 6.8 oz. of gear oil.
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.
If the horsepower of your Mercury outboard lower unit is 75 and below, SAE 80W90 Gear Lube is recommended.
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.
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.
outboard motor will start and idle, but dies out under load
Mercury® Marine High-Performance Gear Lube from Basspro
motor shuts off when put in gear sometimes
What year is Mercury Outboard with serial # 5863149
I had used a high performance gear lube quick silver marine lubricant it is not expensive and works very well
what does a 1991 mercury 150 outboard weigh