When your lawnmower doesn't start well -- or after you get it started, it sputters and dies -- then there is a good chance that the carburettor injector jets and carburettor are gummed up with old gas. Over time, gas deteriorates and any debris in it begins to make the gas gum up inside the carburettor fuel bowl and the carburettor injector area. Cleaning your lawnmower's carburettor jets will get it running smoothly again.
Look under the gas tank on your lawnmower and find the rubber gas line clamped to the tank. Follow the line to the side of the carburettor, where it is clamped onto the carburettor nozzle leading to the carburettor injector jets.
Squeeze the clamp at the end of the rubber gas line with the pliers. Slide the clamp down the gas line several inches. Pull the gas line off the carburettor and direct it into the gas can to collect the gas in the line.
Point the carburettor cleaner spray into the side nozzle of the carburettor. Spray the cleaner into the nozzle for eight to 10 seconds to free up any gummy gas.
Point the canned air into the carburettor and spray it for 15 to 20 seconds. Reclamp the gas line to the side of the carburettor.
Unscrew the bolt on the base of the fuel bowl with the pliers. Pull the fuel bowl off. Dump out the old gas and dispose of it safely.
Spray carburettor cleaner into the fuel bowl and onto the valves and float above the fuel bowl. Replace the fuel bowl and secure it with the bolt.
Add fresh gas to the lawnmower's gas tank.
Work in a well-ventilated area.