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1924 Dodge Choke Set Up


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Recovering from engine fire where back firing ignited  the vacuum tank causing a full engine fire. It took 2 - 10 lb ABC extinguishers which saved car from being a total loss

 

Ignition system gone though with. Cap rotor (with brush) are OK. The points and timing are set per manual

 

Carburetor rebuilt professionally. Understand their is only one adjusting point and the book says to set this adjustment when hand spark control is on retard

 

The choke needs to be pulled out fully to start. As engine warms up and choke pushed,  the engine starts to make a poping sound when pushed in more than 2/3 of full travel.

The engine pops when engine is throttled  up when either the  choke is pulled out over 50% of full travel and when is pushed in 2/3 or more of full travel . In that sweet spot there is no engine poping.

 

The spark control is at advanced during this operation.

 

My guess the above poping is from too lean or to rich mixture

 

Question: Do I just leave it in that sweet spot,  or am I missing something.

 

Not to be rude, but I am only looking for answers from Dodge Brothers members who have personal hands on experience working on their Dodges

 

Art

 

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Hi Art, first thing is the ignition should be retarded, not advanced, when starting.  When things are properly set up, you should be able to push the choke all of the way in when the engine warms up.  It could be a vacuum leak is causing a lean condition and having the choke partially out makes up for it.  I don't know if you are familiar with the carb but there is a possibility that the rack & pinion were not assembled correctly.   I've attached some reference material showing cross sections of the carb.   The choke cable is connected to the bell crank  and on the bell crank pivot shaft is a small pinion gear  that engages a toothed rack.  Pulling out the choke rotates the bell crank and causes the pinion gear to move the rack, which is attached to the fuel metering pin.  So, the tapered metering pin moves down as the choke is pulled out further (bell crank rotates CW).  The pin goes through a hole, called the fuel metering jet. Because of the taper, the fuel flow area between the hole and pin changes depending on pin position.  As the pin moves down, the opening between the hole and pin (annulus) increases, allowing a richer fuel/air mixture.  When assembling the carb,  the relative position of the rack & pinion is important since it sets the metering pin position for driving (engine warm).  If the rack was not fully up and bell crank in position shown in 2nd attachment,  the needle position could be way off.  I would take a close look here and I would also be sure and check static timing if you removed the distributor during the engine work.  The 3rd article I attached goes through the theory and adjustment of the carb.  Good luck!

Stuart Carb cross sect..jpg

Adjusting Stewart Carb-1.jpg

Carb-1.jpg

Carb-2.jpg

Carb-3.jpg

Carb-4.jpg

Carb-5.jpg

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If the bowl is carrying too little gas it will run lean which seems to be the problem.

Remember the only adjustment screw that carburetor has functions opposite from you are used too.

Turning it clockwise makes the mixture more rich.

If the pinion and rack are not properly engaged, good luck, so pay attention to page 23 shown above.

 

On another note the choke isn't a "choke" which restricts air flow.

It's a controlled leak from the fuel bowl.

More properly it should be called a primer as it floods the carb chamber with gas.

You'll find it will start a lot easier if you hold the "choke" out for 2-3 seconds before hitting the starter so the carb is already primed.

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Thank you both for the information. I do have the spark retarded on start up and then advanced  once it is running.  I had never checked the timing before the fire. I did not remove the distributor but did find timing was way off using the static timing  procedure in the manual (#4 exhaust valve)  Have not got a chance to load test the car but it ran smooth in the sweet spot settings as i described above.

 

I will check for the float level and then check vacuum leaks between the carb and block before working with the rack and pinion set up.  Thank you for the help. I now understand how the carb works and thanks for the expanation

 

Art

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  • 5 months later...

Like others, I lost the correct position of the enrichener pin when I took carb apart and put it back together. But I found this procedure quite easy: Remove the arm that connects to the choke cable. That way, you can turn the “choke” adjustment knob by hand. Have somebody crank the engine. Starting in the richest position (knob turned all the way counter-clockwise, very slowly turn the knob clockwise. When the engine starts, you are not far off the correct choke position. Perhaps you are a bit rich. Turn now one way, now the other, to find the best engine running. When satisfied, put the choke cable adjustment arm back on the shaft. Do it such that the adjusting click screw on the carb is around half way. That way you can still adjust leaner or richer.

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  • 4 months later...

Thanks for all the info on the Stewart carburetor, it's been a tremendous help. I'm trying to start a 1916 Dodge Touring which hasn't been run in 15 years. Got it running on the primer cups but nothing going through the carburetor. Pulled it and found it welded together with shellac from old gas. Got it apart without wrecking anything, thanks to your posts. The only problem is I cannot get the float valve seat out of the body. Is there a replaceable seal between the seat and body, or is it a hard seat? I puddled cleaner around the seat and it doesn’t seep out, so I'm tempted to leave it be. Appreciate any help. Charley

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Mike: Thanks for your reply. My concern is that if the gasket is missing, gas will bypass the needle seat and leak or flood all the time. Since it's impossible to remove the seat it may not leak past the threads. I'm going to assemble with needle and banjo housing and air test. See what happens and take it from there.  Charley

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  • 2 weeks later...

Hello my name is Dan I have a 1925 Buisness coupe. The thing is in good shape but it seems that the shaft on the carb where the choke cable attaches is frozen. I took it apart and there is a stringy sticky sealant material. I've came across this on older military vehicles but I can't seem to remember what it's called. And more important I don't know how to replace it. Can I reuse the stuff that was taken out?

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  • 7 months later...

Back on the Dodge. Installed carburetor and got it running intermittently. Got a lot of backfiring then it would run for short period of time and then die. Cleaning fuel system and started on ignition system. 
Charley

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49 minutes ago, olebug said:

Got a lot of backfiring then it would run for short period of time and then die.

"Backfire", firing back through the carb which usually means a lean mixture OR "Afterfire",  in the muffler which usually means a rich mixture??

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Installed inline filter between fuel pump and carburetor, but really haven't run engine yet. However, this car has an electric fuel booster pump that looks like it was factory installed. Just crawled under to check it out and found some kind of a filter/strainer on the pump inlet. Will check it out and while I'm at flush the pump. Vacuum tank is bypassed. Backfiring is in the carburetor, I think it's probably starving. 
Charley

 

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