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1950 Dodge running rough


Noah H

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Hello, I’m new to the forum, I am a young guy who likes working on old cars and tractors. My first car is this 1950 Dodge Meadowbrook. I bought it non running looking for a project, within a week I had it running and driving just in time to drive it to school when freshman year of high school started after summer. Now going starting my senior year the cars engine was completely overhauled by professional flathead rebuilders. And it has been running great. Everything underneath the hood was either rebuilt or replaced. Carb has been rebuilt with a N.O.S kit, vacuum advance is working as it should, the coil is a 6v o Reilly’s coil with a Brillman condenser. There is no ballast resistor. My point is, the car has a slight hesitation when it gets hot, whether is between shifting gears or just sitting a stop  when giving the motor an rpm increase. Then engine was timed by a local trusted engine builder as I watched him do it. The light lines up perfectly with the arrow above the crank pulley. Still a miss. At high rpms/accelerating down the road it runs great . Only mid rpms and between shifting gears and starting from a dead stop there is hesitation. Only when Hot. The car is only a standard fluid drive. any help would be appreciated. Here is some pictures of my journey.

EF3CE657-4B56-408D-8614-DBB2D327BB27.jpeg

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Hesitation or pause only on initial pedal movement?  Either very lean idle or inadequate accelerator pump fuel delivery would be my first guess.  If the pump is providing a good stream, try opening the idle fuel screw 1/4 turn or so.

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Pull a couple of spark plugs cylinders 3 and ,  see how they look. Go online to a site that tells how to read them. Two other possibilities, incorrect float setting, or vacuum path to the step up jet in the carb is blocked. This could be due to an improper or improperly installed carb to manifold gasket. Additionally if your car has an automatic choke check to see if it is fully opened when the engine is at normal running temperature.

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Welcome aboard Noah!

Sometimes these cars have  just a crank pulley and sometimes they have a harmonic balancer. If you have the balancer it might have shifted over the years and the marks are now incorrect.

Do you know how to find TDC on the compression stroke?

 

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The B&B carb on my 218 P15 has three holes in the accelerator pump linkage. This is so the volume of fuel expelled by the pump can be adjusted. You might try moving the wire rod to the hole farthest from the pivot bolt to provide maximum travel of the pump and enrichen fuel mixture as it transitions off of idle.

 

Your car looks great and congrats on putting it back on the road!

Edited by Sam Buchanan
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Thank you all, as I look through the carb and actuate the throttle linkage, there is a solid shot of gas I see as I look through. That would confirm it is not the acc pump? It is a hesitation/ running rough when it seems to warm up to normal operating temps. There is no holes in my linkage as far as a harmonic balanced my vehicle is not equipped with one. While timing the engine he showed me the plug on top of the head, he removed the plug and stuck a long wire in the hole. From there he showed me how to get the engine to tdc. From there we got the engine right on time. I have never adjusted the float. 

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Hey Noah,

Welcome to the forum. From what I hear, you've had your car for close to 3 years. Are you using ethanol or non-ethanol gas? How long has it been since the carb rebuild?  More than a year? Have the carb pulled and cleaned. Also check your fuel filter. Sounds like this problem slowly came on. Probably got some sediment or such in the idle circuit. If you use ethanol gas it breaks down quickly (usually within 3 months) and you get this brown fuzzy residue that is great at fouling the idle circuit. You don't see this on modern cars as much because the fuel system is a closed system and our cars have an open system that lets air in at a lot of points prior to the compression stroke, especially at the carb.

 

Joe Lee

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Thanks Joe, here I use 91 octane premium unleaded gasoline, I have used that ever since I got her running. I never checked the float level. Could it possibly be a float level out of adjustment? Or is that ruled out. 

 

Thanks 

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Hey Noah,

 

While it may be the float, I kinda doubt it. Once a float is set it doesn't just move on its own. You said you use 91 octane unleaded. It probably has ethanol. These old cars burn almost anything and still run good. The trouble I've seen with it is on these cars (IMHO) when you shut down the engine the gas in the carb is boiled away by the heat of the engine. When that happens, the gas level in the carb float bowl is reduced or emptied and the residue above the gas line dries and leaves a very small amount of what is essentially mold from the ethanol. As new gas is put back in the float bowl, this stuff is usually flushed thru the system and burned in the engine. BUT not all is flushed. A little bit remains and eventually will build up and cause rough running or stumbling at idle or low speed due to the size of the idle circuit ports and passages. It takes a while for it to become noticeable, but a good cleaning usually takes care of it. That's why you see a lot of owners run non-ethanol fuel in these cars.

 

If you want you can try a can of Seafoam in the gas tank. This usually cleans out the tank and the fuel lines and carb of most of this crap that is left by the ethanol gas. Before the non-ethanol gas the problem you had used to be water in the gas from humidity and non-scrupulous gas station owners adding water to the gas to make a buck. You see this residue problem more often in cars that do not get used much like the weekend drive or the couple of times a week driving. The longer the car sets the more time the gas has to dry out and leave this residue. I saw this all the time working on ATV's, and jet ski's that set for a while.

 

Joe Lee

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Hey Noah,

 

How did you clean the carb? Just spray it out with carb cleaner and blow thru the ports with compressed air? Usually for a good cleaning you need to soak the carb parts in a solution (you can get the gallon cans at Autozone or such for a reasonable price).

 

My Bad! I just read thru the Plymouth service manual. Check out page 126 section 4 the last paragraph. Mine has the same problem. I'll bet dollars to doughnuts the throttle valve shaft is worn and sucking in air messing up the idle.  Shoulda caught that sooner since mine does the same thing.  Easy way to check is put a dab of grease on the shaft ends on each side of the carb. if this is the problem it will run fine at that point but the grease will melt off in short order. Only way to fix it is a new carb or make some bushings to seal the gap around the shaft.

 

Joe Lee

Edited by soth122003
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Just for info at this point but what is the stamped carb. # that appears on the web above the float bowl.

Is the brand name carter B&B?  It may be something like- D6H2.

 

DJ

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The number on the horn is the carb #. DG61 was for most Plymouth 41-48. DG62 dodges around those years. As far as play around the shaft, if you can feel it, it's worn. If you can't feel it check with a dial indicator. Mine only has about .001 thousandths play it don't take much. and that is radial not axial. Some companies make bushings for this, but it is a hunting game for the right size. Plus the shaft may be worn as well making a bushing a mute point.

 

On mine I just decided to live with it for now. I have a manual choke so for idle and low speeds I have it about 1/4 closed and it helps. The choke plate on my manual choke has a spring tensioner on the plate linkage, so when I apply throttle the air going past the plate forces it open to full. It's a backyard mechanic thing, but it works for now.

 

Joe Lee

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Are you sure you have the 3 speed manual transmission?  Almost all Dodges got the semi-automatic, or Gyromatic, transmission by 1949, except the shorter wheelbase Dodge Wayfarers, which continued with the 1948 type setup of fluid drive with 3 speed manual.  

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Another possibility is an air leak at intake manifold or gasket. I also suggest advancing the timing about 5 deg or until it pings to take advantage of modern gas Jim

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