broker-len

32 Plymouth PA

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I am running the original carb  I rebuilt it       I understand the idle screw works in reverse      I think I am running rich     other that filling up tank putting on miles  and rechecking   how can I tell ?    which jet would most likely affect economy    is there a way to lean it out like the BB1

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Benefits of AACA Membership.

You could have a muffler shop put an oxygen sensor in the exhaust pipe. It will give you a reading of rich/lean. Pretty common thing on carburetted hot rods as an aid to tuning. They are standard on EFI cars.

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I have contacted carb king several times with PM      never answered  me      going to put a BB1 which I have on         better unit

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The Carb King is available by phone Mondays  and Tuesdays see The Carburetorshop .com site .

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4 hours ago, broker-len said:

I have contacted carb king several times with PM      never answered  me      going to put a BB1 which I have on         better unit

 

If you will check our website, you will see that we answer:

 

(1) Questions requesting carburetor kit and price

(2) Questions requesting carburetor availability (but not price, many we have only one).

 

ALL OTHER QUESTIONS SHOULD BE ASKED VIA TELEPHONE

 

Jon.

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Jon-------I have followed the pain that BB and others have gone through with     REBUILT     Brass bowl units    my question was ;   why all the drilling of the jet holes in the 4 page instructions I sent on the PM      -----why is it nesessary for BB and Tom to be redrilling  these holes   is it because they can't get old jets out ?

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No , it is not about getting the jets out . It was fact the rebuilder used non factory parts . These parts were build for a different carb model number . In my and BB case , the idle tube seems to been build for model RJH 150 . The jet hole , ie small bottom intake hole is sized to small for the larger DRT209 carb . Not allowing enough fuel to be drawn up to even start . As soon as i opened this hole to spec size . Carb worked fine . There are two other holes in these tube a vent and restriction passage . I wish , I knew the proper sizes they should be . But must be close as it is working .

 Jon may know if these are the economizer and bypass hole , as those number are listed in spec sheet . ????

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Posted (edited)

Most carburetor idle circuits work the same way.

 

Fuel enters the idle jet through a metering orifice.

 

This is the raw idle fuel.

 

Air is introduced into the raw fuel via the bypass. At this point, the air and fuel are not well mixed. To better mix the air and fuel, this mixture is squeezed through a restriction. Squeezing the mixture causes acceleration of the mixture velocity, which aids in mixing. At varying times, Carter called the restriction a economiser and also a restrictor.

 

So applying this information to the idle tubes on the various brass bowl carburetors:

 

The lower hole just above the threaded plug is the jet size (a #62 drill on the 209S)

 

The next hole(higher) is the bypass (#53 drill on the 209S)

 

The economiser (or restictor) is quite obvious, it is the orifice through the necked-down portion of the tube (#56 drill on the 209S).

 

To finish for those looking at newer carburetors, some idle circuits have an additional air bleed (called an idle air bleed) downline from the restrictor. The 209S does NOT have this feature. When present, the idle air bleed adds additional air to the idle air/fuel mix.

 

There are a number of various repro parts being made off-shore, primarily for the Carter 150S used on 1930~1931 Chevrolets, as these are in sufficient demand to justify limited reproduction. I am unaware (that doesn't mean they don't exist) of any repro parts for the 209S other than those that interchange with the Chevrolet (bowls, floats, etc.) but not calibrated parts. The Chevrolet tube has a smaller orifice, and a larger economiser than the Plymouth.

 

It should be obvious that if the bypass is larger than engineered, the mixture will be lean, and the idle jet orifice will need to be enlarged to compensate.

 

I am aware of two really good rebuilders of the Chevrolet brass bowl carburetors. I do not know if either will work on others or not. These two go by the respective monikers of "chipper" and "junk yard dog" and may be found posting on the VCCA website. I have seen the work done by junk yard dog, and chipper has an excellent reputation, and has had for years. Although I have not personally seen his work. I can recommend both.

 

Jon.

 

 

Edited by carbking (see edit history)
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As to the availability of parts:

 

To my knowledge, only three companies offered parts for the brass bowl carburetors back in the day:

 

(1) Carter (obviously)

(2) Standard Hygrade

(3) Hawk Products

 

Hawk is probably less well-known than the other two. Hawk was located in Indianapolis, and later made carburetor parts for more modern carburetors under the name Sherman.

 

Again, most of the aftermarket stuff was keyed to Chevrolet.

 

Jon.

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Jon    Thank you----other than a bad needle and seat  what could cause the 209S  to run real rich    I set the idle and accelerator properly ?

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