The accelerator pump is actuated by a lever that attaches to the throttle linkage. To remove the air horn, the roll pin that holds the accelerator pump arm will need to be driven toward the air horn. Make sure a gap is left to allow prying the pin back for reinstallation. Many Q-jets have had the air horn casting broken trying to reinstall the accelerator pump arm. All pre-electronic control versions held the air horn to the float bowl assembly with nine screws, feedback designs used 13 fastners.