Although the carburetor is set by the factory, over time it is necessary to periodically adjust the carburetor. Adjusting the carburetor ensures that the engine is getting the proper ratio of fuel mixture. The carburetor on your Toro snow blower is hidden under a heater box to protect it from the elements. There are three adjustment screws to ensure the engine runs smoothly. When turning the adjustment screws, do not force them past their factory set stops. You will feel the pressure of the stops when adjusting the screws.
Place the Toro snow blower outside on a level surface. Locate the heater box over the carburetor. The heater box is on the side of the engine below the air cleaner.
Remove the two screws on the side with a Phillips-head screwdriver and the hex screw on top with a nut driver. Pull the choke knob off the rod and lift the heater box away from the engine. Push the choke knob back onto the end of the rod.
Turn the power adjusting screw on the bottom of the carburetor clockwise with your fingers until you feel some resistance. Rotate the power adjusting screw one full turn counterclockwise.
Find the idle mixture screw just above the side of the carburetor float bowl. Turn the idle mixture screw clockwise with a flat-head screwdriver until you begin to feel some resistance. Rotate the idle mixture screw counterclockwise one and a half turns counterclockwise.
Start the Toro snow blower and allow the engine to warm up for five minutes. Once the engine is warm move the throttle to the "Fast" position.
Rotate the power adjustment screw in 1/8-turn increments until the engine begins to sputter. Turn the screw counterclockwise until it begins to run erratically. Turn the screw back clockwise to the midpoint between the two extremes.
Move the throttle to "Idle" and rotate the idle speed screw clockwise until the engine begins to idle fast. The idle speed screw is above the idle mixture screw.
Turn the idle mixture screw clockwise until you begin to hear a miss in the engine. Turn the screw in 1/8-turn increments. Once you hear the miss, turn the mixture screw counterclockwise until the engine runs rough. Turn the mixture screw clockwise to the midpoint between both extremes.
Rotate the idle speed screw until the engine runs evenly at idle. Check the adjustment moving the throttle to "Fast" and back to "Idle." The engine should accelerate and decelerate without missing or running rough.
Shut off the engine and pull the choke knob off the rod. Place the heater box back over the engine, inserting the choke rod through the hole on the box. Secure the heater box with the retaining screws and push the choke knob back onto the rod.