Abstract: A carburetor includes a body having an inner wall and an air/fuel passageway. An insert includes a base having a shape that closely matches the inner wall and a first tower having a first end disposed within the air/fuel passageway. A main circuit passageway is at least partially formed within the first tower and has a first end in fluid communication with the air/fuel passageway and a second end in fluid communication with the fuel bowl chamber. The main circuit passageway carries fuel from the fuel bowl chamber to the air/fuel passageway during engine operation when the throttle valve is opened. A second tower has a first end coupled to the base and a second end spaced away from the base. The first end of the first tower, the second end of the second tower, and the base are the sole engagement points between the insert and the body.

Abstract: A carburetor includes a body, a throttle valve positioned in an air/fuel passageway in the body, a fuel bowl coupled to the body, a fuel bowl chamber at least partially defined by the fuel bowl, and a one-piece fuel-metering insert coupled to the body. The insert includes an idle circuit passageway having a first end in fluid communication with a fuel passageway in the body and a second end in fluid communication with the fuel bowl chamber. The insert also includes a main circuit passageway having a first end in fluid communication with the air/fuel passageway and a second end in fluid communication with the fuel bowl chamber.

Abstract: A carburetor configured for use with an internal combustion engine includes a body defining a passageway therein, a throttle lever including a cam surface, and a throttle valve positioned in the passageway and responsive to movement of the throttle lever. The throttle valve is configured to rotate about a first axis from a wide-open first position to a second position at least 50 degrees from the first position. The carburetor also includes a choke lever including a follower surface configured to be engaged by the cam surface and a choke valve positioned in the passageway and responsive to movement of the choke lever. One of the cam surface and the follower surface includes an arcuate segment having a constant radius centered on a second axis. The arcuate segment is sufficiently long such that the throttle valve is configured to move at least 15 degrees while the other of the cam surface and the follower surface engages the arcuate segment.

Abstract: A carburetor includes a body, a throttle valve positioned in an air/fuel passageway in the body, a fuel bowl coupled to the body, a fuel bowl chamber at least partially defined by the fuel bowl, and a one-piece fuel-metering insert coupled to the body. The insert includes an idle circuit passageway having a first end in fluid communication with a fuel passageway in the body and a second end in fluid communication with the fuel bowl chamber. The insert also includes a main circuit passageway having a first end in fluid communication with the air/fuel passageway and a second end in fluid communication with the fuel bowl chamber.

Abstract: A carburetor configured for use with an internal combustion engine includes a body defining a passageway therein, a throttle lever including a cam surface, and a throttle valve positioned in the passageway and responsive to movement of the throttle lever. The throttle valve is configured to rotate about a first axis from a wide-open first position to a second position at least 50 degrees from the first position. The carburetor also includes a choke lever including a follower surface configured to be engaged by the cam surface and a choke valve positioned in the passageway and responsive to movement of the choke lever. One of the cam surface and the follower surface includes an arcuate segment having a constant radius centered on a second axis. The arcuate segment is sufficiently long such that the throttle valve is configured to move at least 15 degrees while the other of the cam surface and the follower surface engages the arcuate segment.