A key part of your lawn mower is the fuel system. You need to keep your lawn mower's injectors, carburetor, fuel line and gas tank clean and free of gummy gas so the engine can perform at its best. Keeping the fuel system clean also prevents future expensive breakdowns. You should occasionally use a fuel system cleaner on your lawn mower.
Purchase a fuel system cleaner that is meant for a lawn mower. You can find these at any home and garden store. If you only have car fuel system cleaner, you can use it, but it is more potent.
Fill the gallon jug almost to the top with new, clean gasoline.
Read the instructions on the bottle of fuel system cleaner you are using. For lawn mower fuel system cleaners, it is usually 2 tablespoons of fuel system cleaner per gallon of gas.
If you use a car fuel system cleaner, use half of the ratio on the bottle as the car fuel system cleaner is more potent. For example, the car fuel system cleaner says to add 1 teaspoon for fuel cleaner per gallon of gas; you will use a 1/2 teaspoon per gallon of gas for your lawn mower mix.
Add the correct amount of fuel system cleaner to the gallon jug of gas. Shake the jug several times. Fill the lawn mower gas tank with the fuel system cleaner/gas mixture.
Use the fuel system cleaner once a month throughout the mowing season.