Autolite 1100 Carburetor Adjustments


1100 Float Level

Float Level

Remove the carburetor float bowl top and turn it upside down. Measure the distance from the gasket surface of the top to the crown of the float. Bend the float arm tab as necessary. Due to the ethanol added to our fuel, cheat to the upside. Instead of 15/16, you might try 1″.

1100 Vent Adjustment

Vent Valve Adjustment 
Set the throttle linkage to the hot idle position. The groove in the vent valve rod should now be even with the open end of the vent valve rod retainer. Bend the arm on the vent valve rod actuating lever where it contacts the accelerating pump lever to align the groove with the edge of the bore.

1100 Accelerator Pump

Accelerating Pump
Position the throttle and choke linkage and adjustments so the throttle plate will seat in the throttle bore. Bend the accelerating pump actuating rod to obtain the specified clearance between the pump cover and the roll pin in the pump lever. Gap should be 3/16″

1100 Dashpot

Adjust the throttle position to the hot idle setting. Turn the dashpot adjusting screw in until it contacts the diaphragm. Turn the screw in 3 1/2 turns. A small rod or screw driver, used to depress the diaphragm, will aid in determining when the diaphragm has reached the limit of its travel.

1100 Choke

Manual Choke
Place the choke linkage in the full choke position. Insert a drill or a gauge of the specified size between the long side of the choke plate and the inside of the air horn. Maintaining the full choke position, adjust the choke pulldown nut to just contact the swivel on the cam lever.Idle Mixture Adjustment
This adjustment is done after the carburetor is mounted on the carburetor.

  • Get the engine to operating temperature.
  • Be sure the choke valve is fully open.
  • Adjust the idle to specifications.
  • Turn the idle mixture screw out and/or in until you get the smoothest idle.
    • Option 2 – Attach a vacuum gauge to a vacuum port off of the carburetor and adjust the mixture screw until you get a steady vacuum reading.
    • Option 3 – Turn the mixture screw out 1/2 turn. Turn it in (clockwise) 1/4 turn, hesitate a second, then the next 1/4 turn. Do this until the engine rpm starts to drop. Turn back out (counter clockwise) 1/4 turn.

Fast Idle Adjustment

  • Let the vehicle sit overnight.
  • Open the throttle once to let the choke valve close and the fast idle screw settle.
  • Attach your RPM meter
  • Adjust the fast idle screw until you get to the recommened RPM.

Watch a video about On The Bench Adjustments

Updated on 04/27/2022

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