How to Adjust the Automatic Choke on an Aircooled Volkswagen (VW) Beetle

PDF download Download Article
PDF download Download Article

The automatic choke regulates the air/fuel mixture during engine start up. It produces a richer fuel/air mixture when the engine is cold, then gradually makes the fuel mixture leaner as the engine warms up. This is accomplished by a butterfly valve in the throat of the carburetor, at the very top. When this valve is closed the flow of air is very much reduced and the fuel/air mixture is rich. When the valve is open the flow of air is maximized and the fuel/air mixture should be correct for a warm engine..

Get Car Support Solve Any Problem

wH
Hi there! Do you have a question about how to diagnose or fix a problem with your car? I’ve read the manual so you don’t have to. Select your make, model, and year, then ask away!
*
*

Steps

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/4\/4b\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-1.jpg\/v4-460px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-1.jpg","bigUrl":"\/images\/thumb\/4\/4b\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-1.jpg\/aid1038937-v4-728px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-1.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    [1]
  2. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/1\/15\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-2.jpg\/v4-460px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-2.jpg","bigUrl":"\/images\/thumb\/1\/15\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-2.jpg\/aid1038937-v4-728px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Advertisement
  3. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/b\/b3\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-3.jpg\/v4-460px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-3.jpg","bigUrl":"\/images\/thumb\/b\/b3\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-3.jpg\/aid1038937-v4-728px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    • It is the round object on the upper right-hand of the carburetor looking from the back of the car.
    • There is a wire coming to it from the positive side of the coil. Check this with a trouble light for voltage when the key is on.
    • The choke is held in position by a triangular ring clamp and three screws so it can be loosened and rotated for adjustment.
  4. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/3\/3f\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-4.jpg\/v4-460px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-4.jpg","bigUrl":"\/images\/thumb\/3\/3f\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-4.jpg\/aid1038937-v4-728px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-4.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Pull the throttle arm on the left side of the carburetor down to free the cam (little step arm) that the screw at the top of the throttle lever rests on. [2]
    • With the engine cold, the butterfly valve should be closed.
    • As the engine warms up, the coil voltage heats an element inside the automatic choke, causing a bi-metal spring to uncoil, opening the butterfly valve, and moves the cam to reduce the idle speed.
  5. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/8\/86\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-5.jpg\/v4-460px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-5.jpg","bigUrl":"\/images\/thumb\/8\/86\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-5.jpg\/aid1038937-v4-728px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-5.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    [3]
    • When cold, the little screw at the top of the throttle arm should now rest on the top step of the stepped cam.
    • This sets the hi-idle, which is needed together with the choke on a cold engine to provide sufficient idle speed to keep the engine running until it warms up fully.
  6. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/7\/7b\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-6.jpg\/v4-460px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-6.jpg","bigUrl":"\/images\/thumb\/7\/7b\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-6.jpg\/aid1038937-v4-728px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-6.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    [4]
  7. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/9\/9c\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-7.jpg\/v4-460px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-7.jpg","bigUrl":"\/images\/thumb\/9\/9c\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-7.jpg\/aid1038937-v4-728px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-7.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    [5]
    • Turn the choke element clockwise until the butterfly is standing straight up. Then turn the choke counterclockwise until the choke butterfly fully closes (not too tight).
  8. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/2\/2d\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-8.jpg\/v4-460px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-8.jpg","bigUrl":"\/images\/thumb\/2\/2d\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-8.jpg\/aid1038937-v4-728px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-8.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
  9. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/5\/59\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-9.jpg\/v4-460px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-9.jpg","bigUrl":"\/images\/thumb\/5\/59\/Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-9.jpg\/aid1038937-v4-728px-Adjust-the-Automatic-Choke-on-an-Aircooled-Volkswagen-%28VW%29-Beetle-Step-9.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>License: <a target=\"_blank\" rel=\"nofollow noreferrer noopener\" class=\"external text\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc-sa\/3.0\/\">Creative Commons<\/a><br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    • As the engine warms up, make sure that the butterfly opens until it is standing fully open when the engine is fully warm.
    • If it doesn't fully open,put your finger briefly on the ceramic of the automatic choke and see if it is hot. If not- you need a new one. Try it again in the morning and see if it opens enough to drive it. Check that it is wide open when warm. Re-adjust until you get it right.
    10. Advertisement

Community Q&A

Search
Add New Question
  • Question
    What should I do if the vehicle won't turn on again after I turn it off, and the butterfly stays open?
    Jkchd07
    Community Answer
    Check your battery connection first. If there isn't a good ground connection, it won't come on.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 0 Helpful 3
Ask a Question
200 characters left
Include your email address to get a message when this question is answered.
Submit
      Advertisement

      Tips

      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Submit
      Thanks for submitting a tip for review!

      Warnings

      • Safety should always be your #1 focus when working on a vehicle. ABSOLUTELY NOTHING in this world is so important, that you should EVER practice unsafe maintenance on your vehicles. Always use the proper tools for the job at hand. Common sense is VERY IMPORTANT. I try to ensure the pages I add are error-free; however, I am human and make mistakes.
        Thanks


      Advertisement

      You Might Also Like

      How to Reset a Traction Control Light (TCS)
      How to Reset a Gas Gauge Needle
      How to
      Recharge the Air Conditioner in a Car
      How to
      Change an Oxygen Sensor
      How to Reset Your Steering Angle Sensor Without an OBD-2
      Quick and Easy Steps to Reset the Maintenance Required Light
      What to Do If Your Car’s Anti-Theft System Prevents It from Starting
      How to Unlock the Hood of Your Car
      How to
      Fix a Locked Steering Wheel
      How to Get Out of Limp Mode: 5 Ways to Bypass, Signs, & More
      Car Not Starting, but Still Has Power? These Are the Most Common Causes
      How to
      Fix a Cigarette Lighter in a Car
      How to
      Open a Hood with a Broken Latch
      How to
      Determine Gear Ratio
      Advertisement

      References

      1. ↑ https://www.holley.com/blog/post/how_to_adjust_a_carburetor_automatic_choke/
      2. ↑ https://www.youtube.com/watch?v=8iF5sewX6UU
      3. ↑ https://www.youtube.com/watch?v=8iF5sewX6UU
      4. ↑ http://www.vw-resource.com/automatic_choke.html#adjust
      5. ↑ http://www.vw-resource.com/automatic_choke.html#adjust

      About This Article

      Thanks to all authors for creating a page that has been read 117,576 times.

      Did this article help you?

      Advertisement