Your Troy-Bilt tiller may be a garden workhorse, but a dirty carburetor brings it to a halt. The tiller's 4-cycle engine relies on its carburetor to combine the right mix of gas and air, and keep that engine running smoothly. Dirt and deposits that clog carburetor fuel and air passages leave your tiller's engine surging and dying. Basic carburetor cleaning on a midsize Troy-Bilt engine solves the majority of carburetor-related performance problems. Cleaning the carburetor is a straightforward process that doesn't require special training or experience. With some basic steps, your Troy-Bilt tiller can quickly be garden-ready again.
Remove the air filter assembly to expose the carburetor. Lift off by hand the filter cover and the air filter, located at the engine's right-front top. Use a screwdriver to unscrew the two mounting screws holding the upper air filter base in place -- one at the front corner, one directly beneath where the filter sat -- and remove the upper air filter base.
Remove the lower air filter base. Use a socket wrench to remove the bolt at the base's top back corner and the two nuts on the lower front. Pull the section forward and disconnect the breather hose tube at the back. The carburetor assembly, with its distinctive bowl, is directly behind the base. Pull off the lower air filter base.
Lift the choke control lever off the top right-hand corner of the carburetor. Clamp off the fuel line leading to the carburetor's lower right side with a pair of hose clamp pliers. Use needle-nose pliers to loosen the hose clamp holding the fuel line to the carburetor. Slide the loosened clamp up slightly, then slide the hose off the carburetor. Move your catch pan beneath the hose to catch remaining fuel.
Remove the gasket sitting in the front of the carburetor, and slide the carburetor forward on the two mounting rods that support it. Disconnect the two linkages that connect to the carburetor at the top back. Pull the carburetor forward and off its two mounting rods.
Remove the bowl, held on the carburetor's bottom with a single nut. Hold it over the catch pan; it will have fuel inside. Examine the float bowl for dirt and debris in the fuel. Remove the rubber O-ring that sealed the bowl to the carburetor body. Examine the O-ring for signs of cracking or shrinkage that warrant replacement.
Turn the carburetor on its back and remove the movable, U-shaped float. Use needle-nose pliers to pull the small metal hinge pin that holds the float in place, then lift the float off. Remove the inlet needle hanging from its slot in the float, right behind where you pulled the pin. For basic cleaning, disassembling stops here.
Hold the carburetor over your catch pan, and spray all the external and internal surfaces liberally and thoroughly with aerosol carburetor cleaner. Use the spray's directional straw to spray down into all the small openings. Spray cleaner on a lint-free rag, and clean the bowl, needle, gasket and O-ring. Blow the carburetor off with compressed air, if available.
Reassemble the carburetor, working in reverse order. Insert the needle into its slot on the float. Place the float/needle assembly back in the carburetor, and slide the hinge pin back in place. Place the rubber O-ring that seals the carburetor bowl to the body, reattach the bowl, and replace the nut that holds the bowl.
Slide the reassembled carburetor back on to the mounting posts. Reconnect the two linkages at the top back, and slide the gasket into place in front of the carburetor. Reattach the fuel line to the carburetor, and slide the hose clamp down into place. Remove the hose clamp pliers from the hose. Slide the choke control lever back onto the top of the carburetor.
Reinstall the lower air filter base, reconnecting the breather hose on the back. Secure the base with the two nuts and bolt, and reinstall the upper air filter base and its two screws. Place the air filter on its base, and reinstall the air filter cover.