WDO Carburetor Mod's

hudsonguy
hudsonguy Senior Contributor
edited November -1 in HUDSON
A while back, there was some discussion regarding carburetor modifications for running on today's 'higher combustion temperature' unleaded gas. I did a search on old threads and came up empty.



So I was wondering, when rebuilding my '49 Carter WDO 2-barrel carburetor, what suggestions are there for any modifications or adjustments, etc.?



I think I remember someone advising to lower the float setting slightly. How much should this be done?



Also, the manual calls for a long stepped gauge to be used to adjust the metering rods. Does anyone actually have one of these? There is supposed to be a (.001-.005) clearance to this gauge, so it's a very precise setting.



I found a note in the manual that described this gauge as 2.280" in length, so I could probably just try to make one from a piece of welding rod, or something. It seems like without this tool, the adjustment of the metering rods must just be a trial and error thing. I know from experience that sometimes this works, and sometimes it doesn't. My carb is currently in the 'error' stage. Low speed circuitry and running is near perfect, but above 20 mph you can feel a steady, slight 'stumble'. I can see when under the hood that these surges are caused by the metering rods jumping up and down.



Thanks as always for any and all of the great advice on this forum.



Hudsonly,

Doug

Comments

  • [Deleted User]
    [Deleted User]
    hudsonguy wrote:
    A while back, there was some discussion



    Also, the manual calls for a long stepped gauge to be used to adjust the metering rods. Does anyone actually have one of these? There is supposed to be a (.001-.005) clearance to this gauge, so it's a very precise setting.



    I found a note in the manual that described this gauge as 2.280" in length, so I could probably just try to make one from a piece of welding rod, or something. It seems like without this tool, the adjustment of the metering rods must just be a trial and error thing. I know from experience that sometimes this works, and sometimes it doesn't. My carb is currently in the 'error' stage. Low speed circuitry and running is near perfect, but above 20 mph you can feel a steady, slight 'stumble'. I can see when under the hood that these surges are caused by the metering rods jumping up and down.



    Thanks as always for any and all of the great advice on this forum.



    Hudsonly,

    Doug



    did anyone ever come up with a J-1305 tool for this adjustment or even a detail drawing of one ?

    davidh
  • hudsonguy
    hudsonguy Senior Contributor
    Ken U-Tx wrote:
    This is like the chicken and the egg quandary, cause and effect...... the metering rods are held down against a spring by engine vacumm. If the metering rods are fluctuating up and down , thats means the vacumm is fluctuating. Causes: vacumm leaks, misfiring, leaky high speed, or accellerator pump circuit(s), high float setting, and several others...There is a vacumn passage for the piston that pulls the choke open against the spring as well as pulls the metering rod down against its spring....if this passage is blocked by dirt or carbon, that can result in the metering rod staying up off the jet or fluctuating, with resulting rich mixture and engine stumbling. Ken U-Tx



    Boy, how time flies! When I posted this originally over two years ago, it was just two days after starting my 'new' rebuilt engine. It seems so long ago....since then, I've put 12,000 miles on it, part of which was one cross country trip. It actually runs just the opposite now (I know I swapped out rebuilt carbs since then). There's the tiniest stumble at idle, but everything above that is smooth as silk.



    I was able to locate a tool for my WDO. I bought it from John at The Carburetor Shop; http://www.thecarburetorshop.com/Carter_tools.htm

    I don't remember the gauge part number offhand, but it was a T-109-something. I know it's in the manual (at home)



    That reminds me, I've got to pick up the gauge for a WA-1, for next year's Twin H 'upgrade'.
  • hudsontech
    hudsontech Senior Contributor
    I was able to locate a tool for my WDO. I bought it from John at The Carburetor Shop; http://www.thecarburetorshop.com/Carter_tools.htm

    I don't remember the gauge part number offhand, but it was a T-109-something. I know it's in the manual (at home)





    The gauge part number is T-109-113 (2.280 inches) according to the Carter spec sheet I have.





    Hudsonly,

    Alex Burr

    HudsonTech

    Memphis, TN

    NEChudsontech09@yahoo.com (Drop the NEC)
  • [Deleted User]
    [Deleted User]
    i was hoping someone would have one i could rent. . . a guy should need it once only. . .



    or a drawing of one so a fella could make one.



    im not not really a tightwad, only trying to save a buck or two for gas. .
  • [Deleted User]
    [Deleted User]
    I was reading in my Jack Clifford reprinted manual, that the WDO and WGD needs no "rod gauge" for the metering rods. Only the WA-1 mentions the use of a gauge rod.



    It basicly says:



    With the accelerator pump properly adjusted (another topic), run the idle stop screw out until the butterfly closes off inside the baseplate completely.



    Hold the vacumeter link (the piece suspending the rods) down fully, seating the rods in the lowest position possible.



    Then loosen the screw holding the vacumeter arm, rotate it until it comes into contact with the vacumeter link, then tighten. Its adjusted.



    That's all I've ever done, and it seems to work just fine. A bigger problem is worn jets and rods, that fine little hairspring holding the rods onto the vacumeter link - eventually causes the rods and jets to wear out of tolerance. There is the culprit on many a rich-ish WDO and WGD.



    Mark
  • [Deleted User]
    [Deleted User]
    thanks a bunch. ill take a stab at that today. happy weekend !
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