Ventilate the area well. Wear eye protection and chemically stable gloves. Follow the gas line on the side of the engine to the Walbro carburetor.
Remove the clamp that holds the nozzle in place and remove the gas line from the carburetor. Place the line into the bucket to catch gas leaking out. Drain the gas. Close the shut-off valve if there is one. Examine the gas line and check for any damage. Replace the gas line if necessary.
Remove the air filter by twisting the small, plastic, enclosed filter counterclockwise. Inspect it for damage. Clogged paper-type filters require replacement. Undamaged foam elements can be reused. Wash the foam element in warm soapy water. Dry it off and coat it in a few drops of engine oil.
Read the safety data for the carburetor cleaner very well, as carburetor cleaners usually contain chemicals which strip paint, eat through plastic and can be poisonous and extremely flammable.
Disassemble the carburetor. Remove the screws which hold the carburetor body to the float bowl using a screwdriver. Remove the main jet along with its ring using a hex driver. Set both aside for cleaning. Draw a diagram as you go along to help you to remember exactly where everything goes when putting the carburetor back together again.
Clean each part of the carburetor carefully and thoroughly using the carburetor cleaner and the lint-free rags. Ensure that your eyes and skin are adequately protected. Blow through small holes and orifices with the compressed air and the carburetor cleaner. Keep cleaning with new, clean rags until there is no more residue left on the rags. You may need to use a wooden toothpick to poke through the 0.5 mm hole on the side of the carburetor. Fine-wire wool with the carburetor cleaner may be required on the float hinge pin if there is rust buildup.
Lay the pieces on dry rags to dry. Reassemble the carburetor parts in reverse of removal, making reference to the diagram you drew.