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1920 Dodge Carburetor Issue


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My Detroit lubricator carburetor has been sent out twice to two different shops for a complete rebuild and still does not work properly. It runs too lean and the lean condition popping is present. Increasing choke makes no difference. The car can not be driven

 

My experience with popping carburetors on Doges with Vacuum tanks is that if the engine is not immediately shut down, the carburetor will back fire into the vacuum tank and cause a major engine  compartment fire (this happened to my 1924 Dodge)

 

Since their is no fuel adjustment other than idle mixture i can not make the mixture richer. I have dumped over$400  into it and have spent about 8 hours on it with my friend who is a retired mechanic

 

1) The car has been timed per Dodge Manual and does start up. It will not idle and will not run unless the accelerator  is continually pump.

2) When running using the above technique , it will not keep running regardless of hand throttle control

3) The car once ran well but was not used for several year do to family issues

 

Has anyone used the Dayton up draft carburetor where there is fuel adjustment

 

I do not care if I am  not using an original carburetor. I want a car that runs and run safely

 

Art Lee

Dodge Brothers Club Member

 

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First, allow me to state we were not one of the shops mentioned, nor do we still rebuild; so not grinding my own ax!

 

Having said that: there is no better performing or more reliable carburetor to put on that Dodge  than the original Detroit Lubricator/Stewart!

 

Don't know where you were able to get that carburetor rebuilt once, let alone twice, for only $400., but that might be a whole lot of the problem, assuming the carburetor was the issue.

 

Have you done a compression test? A car that has sat for several years just might have sticky valves, which would contribute to low compression, and coupled with an updraft carburetor, a very lean condition.

 

The carburetor has no accelerator pump. Pumping the throttle only really exercises your ankle ;) 

 

Would suggest both a compression test and an ignition test; the carburetor, regardless of the $400. rebuild, might be OK.

 

If both compression and ignition are good, maybe some of the Dodge folks here can recommend a rebuilder who has the expertise and the special tools REQUIRED to properly service the original.

 

Hope you figure it out.

 

Jon

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Art, I thought that the pinion gear and rack on the Stewart carburetor, which you seem to be referring to as an idle adjustment, actually lifts the air valve and thereby controls not only the idle mixture, but also the main mixture.  If anyone disagrees, please correct me.  Is your air valve not lifting enough, or too much, for some reason?  Has it perhaps become detached from the rack, making proper adjustment impossible?  I think that originally the air valve was only swaged onto the rack, and it will come loose after many years.  I had to solder mine back onto the rack.  At first glance to the uninitiated, who may not be clear on the carb's theory of operation, when the air valve and rack become separated it is not obvious that they need to be firmly attached to each other.

 

 

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I hesitate to post the following, however:

 

From "Stewart Dodge Model 25 Booklet"

 

THE METERING PIN SHOULD NOT BE TAMPERED WITH UNLESS ABSOLUTELY NECESSARY.

 

From another source not often, if ever, seen on the internet.

 

When replacing a carburetor that has been taken apart, trouble may be experienced in getting proper adjustment, due to wrong assembling of dash control lever or metering pin. If adjusting screw can not be moved far enough to get proper adjustment, remove dash control lever from its shaft and turn shaft to right or left, with pliers, until proper adjustment is secured. Turn to right for lean and to left for rich mixture.

 

Turn adjusting screw until it is about in the middle of its up and down travel and replace dash control lever on shaft with its arm in contact with point of adjusting screw.

 

Jon.

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  • 2 weeks later...

I have found that adjustment is most successful with the carburetor off of the engine.  I start by using a hack saw to put a slot in the mixture adjusting shaft (to avoid using pliers on the delicate splines on the shaft).  Remove the bell crank to cut the slot, even better remove the shaft assembly to to do so.  Reinstall the shaft.  slide the bell crank over the shaft of a screw driver that fits the slot you cut.  Using the screw driver to rotate the shaft you will feel the metering pin meet (and lift) the dashpot.  This is a matter of "feel".  Once you are confident that the pin is just meeting the dashpot, back the shaft off so it just clears the dashpot. slide the bell crank onto the adjusting shaft such that the stop meets the end of the stop screw on the bottom cover.  Tighten the clamp screw on the bell crank.  The idle adjustment on the throttle shaft is the only other adjustment.  

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  • 3 weeks later...

Jon

 

Thank you for your comments.  You nailed the problem.Compression was way off in 2 an 3 cylinders. Removed head (was leaking a little anti freeze at head gasket) and found both exhaust valves were sticking.

 

Art

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