Carter Carb A/F Mixture

Discussion in 'Technical' started by NewMaverickGuy, Jan 31, 2019.

  1. NewMaverickGuy

    NewMaverickGuy Member

    Joined:
    Jan 21, 2018
    Messages:
    156
    Likes Received:
    13
    Trophy Points:
    41
    Garage:
    1
    Location:
    Birmingham, AL
    Vehicle:
    1970 Ford Maverick
    Thank you. I thought I was never going to find that again. It looks like #5 will be the one I need to do. Could i be getting this much of a vacuum leak from my hoses? They dont feel rotten or hardened. the connections are sealed well and tight. Maybe theres a diffuse leak through the full length of the hose? I know im not having a carb base gasket leak. The transmission vacuum line doesnt leak. Also, can my timing affect my optimum a/f ratio?
     
  2. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

    Joined:
    Apr 30, 2004
    Messages:
    6,493
    Likes Received:
    937
    Trophy Points:
    426
    Location:
    Wisconsin
    Vehicle:
    70 Maverick Grabber, 72 Maverick Grabber Restomod
    Timing and other ignition problems can absolutely mimic carb issues. Have you checked timing - idle and all in numbers and have you checked vacuum readings?
     
  3. Krazy Comet

    Krazy Comet Tom

    Joined:
    Sep 13, 2012
    Messages:
    7,560
    Likes Received:
    2,319
    Trophy Points:
    531
    Garage:
    1
    Location:
    Chesapeake VA
    Vehicle:
    1972 Comet GT clone 306 . 1969 Fairlane Cobra 428CJ 1988 T-Bird awaiting 331 ..
    You may be activating the vacuum advance, which "peps up" performance. No vacuum to diaphragm, no advance, try driving it with advance disconnected.
    .
     
  4. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

    Joined:
    Apr 30, 2004
    Messages:
    6,493
    Likes Received:
    937
    Trophy Points:
    426
    Location:
    Wisconsin
    Vehicle:
    70 Maverick Grabber, 72 Maverick Grabber Restomod
    I looked up specs on 1970 200 distributor - has 7 degrees vac adv / 16 deg mechanical adv / 6 deg book setting at idle. Like all factory settings, these are lower than the engine will like for a little more power.
     
    Last edited: Feb 1, 2019
  5. NewMaverickGuy

    NewMaverickGuy Member

    Joined:
    Jan 21, 2018
    Messages:
    156
    Likes Received:
    13
    Trophy Points:
    41
    Garage:
    1
    Location:
    Birmingham, AL
    Vehicle:
    1970 Ford Maverick
    I've timed it, with a timing light of course, with the vacuum advance disconnected and the line plugged.
     
  6. NewMaverickGuy

    NewMaverickGuy Member

    Joined:
    Jan 21, 2018
    Messages:
    156
    Likes Received:
    13
    Trophy Points:
    41
    Garage:
    1
    Location:
    Birmingham, AL
    Vehicle:
    1970 Ford Maverick
    I've driven it with the lines disconnected and plugged and i still have to do the same thing.
     
  7. mojo

    mojo "Everett"- Senior Citizen Supporting Member

    Joined:
    Jul 20, 2009
    Messages:
    5,250
    Likes Received:
    818
    Trophy Points:
    498
    Garage:
    1
    Location:
    Chicago
    Vehicle:
    73 Comet GT-302 4bl
    What is the possibility your taking air in around the throttle plate shaft ?
     
  8. NewMaverickGuy

    NewMaverickGuy Member

    Joined:
    Jan 21, 2018
    Messages:
    156
    Likes Received:
    13
    Trophy Points:
    41
    Garage:
    1
    Location:
    Birmingham, AL
    Vehicle:
    1970 Ford Maverick
    Well with some tinkering i found out that theres no difference whether or not i have the manifold line connected to the distributor. As if i just have the line open
     
  9. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

    Joined:
    Apr 30, 2004
    Messages:
    6,493
    Likes Received:
    937
    Trophy Points:
    426
    Location:
    Wisconsin
    Vehicle:
    70 Maverick Grabber, 72 Maverick Grabber Restomod
    Plug the manifold hose and leave the inner hose disconnected for now. The retard is not needed for proper engine function. Do you have a vacuum hand pump to see if the advance is working properly? Make sure that hose goes to carb vacuum. Check with the timing light to see if you're getting proper advance.
     
    Krazy Comet likes this.
  10. NewMaverickGuy

    NewMaverickGuy Member

    Joined:
    Jan 21, 2018
    Messages:
    156
    Likes Received:
    13
    Trophy Points:
    41
    Garage:
    1
    Location:
    Birmingham, AL
    Vehicle:
    1970 Ford Maverick
    I did as you said and now it seems like the vacuum advance is working. Could the lean condition be caused by not having a muffler? I just have a motorcycle megaphone tip to make it deeper-sounding so its not so raspy. The original muffler wasnt doing much. It was essentially junk.
     
  11. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

    Joined:
    Apr 30, 2004
    Messages:
    6,493
    Likes Received:
    937
    Trophy Points:
    426
    Location:
    Wisconsin
    Vehicle:
    70 Maverick Grabber, 72 Maverick Grabber Restomod
    I don't think the missing muffler would do anything if the pipes are still on there.
    You are running an air cleaner - yes?

    Did you put a vacuum gauge on it yet? (manifold vacuum)
     
  12. NewMaverickGuy

    NewMaverickGuy Member

    Joined:
    Jan 21, 2018
    Messages:
    156
    Likes Received:
    13
    Trophy Points:
    41
    Garage:
    1
    Location:
    Birmingham, AL
    Vehicle:
    1970 Ford Maverick
    Air cleaner - yes of course
    Vacuum gauge - i dont have one

    Would this vacuum advance be adjustable?
     
  13. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

    Joined:
    Apr 30, 2004
    Messages:
    6,493
    Likes Received:
    937
    Trophy Points:
    426
    Location:
    Wisconsin
    Vehicle:
    70 Maverick Grabber, 72 Maverick Grabber Restomod
    The shop manual make no reference to any adjustment on the dual diaphragm advance.

    I consider a vacuum gauge to be an essential tool for anyone that wants to work on these older engines. There is a great deal you can tell about your engines condition. I suggest a trip to your local parts house Saturday to pick one up. They don't cost much. They might even have one in their customer loaner tools.
     
  14. NewMaverickGuy

    NewMaverickGuy Member

    Joined:
    Jan 21, 2018
    Messages:
    156
    Likes Received:
    13
    Trophy Points:
    41
    Garage:
    1
    Location:
    Birmingham, AL
    Vehicle:
    1970 Ford Maverick
    I've solved my a/f mixture problem. I'm still having symptoms of my vacuum advance not functioning. Where could I find a new vacuum advance unit? I would prefer to just replace this dual diaphragm one with a single diaphram.
     
  15. Acornridgeman

    Acornridgeman MCCI Wisconsin State Rep Moderator Supporting Member

    Joined:
    Apr 30, 2004
    Messages:
    6,493
    Likes Received:
    937
    Trophy Points:
    426
    Location:
    Wisconsin
    Vehicle:
    70 Maverick Grabber, 72 Maverick Grabber Restomod
    Lots of them on ebay. Both Ford and aftermarket. They are easy to swap. If you are not concerned about originality switching to a single is the way to go.

    So what did it turn out to be for the carb issue?
     

Share This Page