Current time: 01-17-2017, 04:01 AM Hello There, Guest! (LoginRegister)

Welcome to!

You are currently viewing the board as a guest. Please Register or Login for full functionality

If you registered and did not receive your email validation, please send a contact note to the admin by clicking here and filling out the short form.

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Carburetor Problem?
Author Message

72 Azure

Posts: 20
Joined: Dec 2010
Region: Not Selected
Reputation: 0


    Post: #1
    question Carburetor Problem?

    Whenever I start up my car it idles high because I have to pump the gas for it to start. Aside from starting it, if I rev the engine it will idle even higher which leads me to believe something is sticking or getting stuck. The only way I can lower the rpm is by pumping the gas and hoping it drops down to the normal rpm.
    Is my carburetor to blame and does the cold weather play a part?
    Away 01-11-2011 05:25 PM
    Find all posts by this user Quote this message in a reply

    [Image: NYtechDan.png]

    My world is fire and blood.

    Posts: 2,995
    Joined: Jul 2010
    Region: Northeast
    New York
    Reputation: 139

    A+ Writing Meet and Greet 1 - 4 Tutorial Coin Shooter

      Post: #2
      RE: Carburetor Problem?

      Well a few things here

      1) do you have the original carb on the engine or an aftermarket carb?

      2) do you have a choke on your carb?

      3) have you checked the throttle linkage by itself to make sure it's not binding on anything and moves freely from idle to WOT?

      Let's say you checked the linkage and discover nothing is binding:

      If you have a choke check it's settings, is it fully opening when warmed up?

      Depending on what carb you have you may have the option of a startup idle setting.
      This is a lever usually connected to the choke, that forces the base idle Rpms up until the choke is fully disengaged. This helps during a cold start and while the engine is warming up to prevent misfires and stalling and acceleration issues. This is why you want to make sure the choke is working correctly.

      Let's say you found no problems with the linkage , and your choke is working correctly and it is set correctly and the problem is still there.

      You may have a vacuum leak somewhere, look around for any vacuum lines that may have popped off, you can try placing your hands over the carb when the engine is running and try to stall it by choking off incoming air. If you totally close off the intake to the carb and the engine is still running then you know the engine is pulling in extra air from somewhere else which is increasing engine Rpms.

      Now you could also have a sticking vacuum advance or a sticking mechanical advance in the distributor.

      First I would look for a mechanical issue.

      Disconnect the throttle cable to the carb, move the butterfly by hand rev the carb from the engine bay, and make sure idle returns back to normal feel for any sticking when you move the throttle lever.

      Next check the accelerator pedal for any sticking, there is a large return spring built into the throttle cable make sure the spring isn't broken or collapsed and the pedal returns to the correct hieght inside the car.

      Inspect your choke make sure its not sticking or out of adjustment.
      Make sure it fully opens when the engine is at tempature.

      Check the issue with the thottle when the engine is warmed up if it goes away then it could be the choke.

      Once you ruled out any mechanical binding of the throttle then move on to more radical things.

      Checking the movement of the throttle by hand and feeling for any binding is important, it could be as easy as the butterflies getting hung up on the air intake, and just loosing the mounting bolts for the carb and jiggle the base so you have free movement.

      After mechanical things binding start checking for vacuum leaks.

      If you find the linkage always returns to the same position and you can't find or hear any vacuum leaks, then hook up a timing light and inspect the base Timing of the motor, if it changes by the throttle position does not then suspect an issue in the distributor.

      Post some feedback on what you tried and what happened.
      Offline 01-11-2011 06:16 PM
      Find all posts by this user Quote this message in a reply

      72 Azure

      Posts: 20
      Joined: Dec 2010
      Region: Not Selected
      Reputation: 0


        Post: #3
        RE: Carburetor Problem?

        Thanks for the reply 72HCode. Sorry for such a late reply, I've been busy and haven't had a time to check out the carb. Just letting you know I appreciate the advice and will put it to use when I get a chance Smile
        Away 01-16-2011 11:09 PM
        Find all posts by this user Quote this message in a reply

        Possibly Related Threads...
        Thread Author Replies Views Last Post
          Problem Repop Parts? basstrix 3 570 09-08-2015 11:47 AM
        Last Post: 72HCODE
        runninpony Temperature Idiot light, problem uk1973 14 1,313 05-07-2015 06:09 PM
        Last Post: uk1973
          Should My New Holley Carburetor Smell Like Fuel? salhi_aemr 4 648 12-31-2014 08:32 PM
        Last Post: Mister 4x4
          Ignition switch problem 1971mach1 22 3,880 12-10-2014 01:47 PM
        Last Post: Twins
          New carb brings new problem snakebite8 4 501 03-21-2014 09:40 AM
        Last Post: Jeff73Mach1
          Fuel reaching the carb problem snakebite8 6 777 10-25-2013 05:15 AM
        Last Post: snakebite8
          Which carburetor on 72 4V CJ marks73 9 1,602 09-01-2012 11:36 PM
        Last Post: cudak888
          Finally bought my personal car haulers - problem though BigPinoyHunk 21 3,131 02-27-2012 02:06 AM
        Last Post: BigPinoyHunk

        User(s) browsing this thread: 1 Guest(s)