A 1998 model 4hp Merc outboard runs on a 50:1 fuel to oil ratio. This works out to roughly one pint of 2cycle oil to six gallons of fuel.
A 4hp Mercury outboard requires a 50:1 fuel to 2 cycle oil mix.
one liter fuel 10 mill oil
0.020 in.
To find out how old a 4HP Mercury outboard is, you can look at the label on the transom bracket, where you will see a two digit number giving you the year it was built.
A ratio of 50:1 would be required, this is roughly one pint of 2 cycle oil, to six gallons of fuel.
The serial number 5591101 on a Mercury 4hp outboard motor indicates that it was manufactured in 1982. Mercury outboard motors typically have a serial number system that correlates to specific production years, and this number falls within the range for that year. For precise identification, you can also check the manufacturer's resources or consult a Mercury dealer.
A 4hp Johnson outboard motor typically uses a mixture of gasoline and 2-cycle oil, usually in a ratio of 50:1 or 100:1, depending on the specific model and year. It's important to consult the owner's manual for the exact fuel-oil ratio recommended for your particular motor. Using the correct mixture helps ensure optimal performance and longevity of the engine. Always use fresh, unleaded gasoline to avoid potential issues.
Mine is a 2000 model and it has an NGK R BPR7HS10
If manufactured prior to 1965, a 24:1 ratio is required. Models 1966 and later use a 50:1 fuel to 2 cycle oil ratio.
The points gap on a Merc 40 4hp is .020
BJ4BRE1A Is made in 1991 and the Fuel mix is 50 to 1
You may have mistaken the '1' for a '2'..if your engine is a 4hp 2 cylinder it dates from 1978.