Sticking throttle

[38plymouth]

And.....the throttle is starting to stick again. I have barely driven the car. I'm so tired of this carb and its stripped screws and leaks. So, I am looking at daytona parts company UN2 universal single barrel replacement carb. Have any of you replaced your b and b with one of these?

[Sniper]

I will say that I have seen a poor ground cable cause sticking throttle issues in other applications. Ground will seek whatever path they can find and if that happens to be the follow linkage it'll use it.  What I would do is put the car in neutral set the parking brake shot the wheels start the engine up and then work the throttle from under the hood and see if it sticks. If it does disconnect the throttle linkage from the carb and work the auto Again by hand and see if it sticks that at least narrow down where the problem area is

Edited August 20 by Sniper

[38plymouth]

It sticks with or without the linkage hooked up. It's the throttle shaft itself I imagine it's fairly worn and I know it leaks a little vacuum. This carburetor is just worn out I have rebuilt it so many times in the last 20 something years. These new carburetors are 300 bucks and they say it is a direct bolt on to my car and they're about 45 minutes from me I'm hoping I can drive over there and see one in person.

[grea235]

I don't know if this would help, but I  recently had an issue with one of my D6A2's.  The throttle was intermitently sticking.  I have it on the long throw setting and the lower flat part of the accelerator pump was rubbing against the hole in the bottom of the body.  When it is set at the short throw hole it was fine because the angle is narrower.  I looked at a couple of my old bodies and I could see rubbing as well.  I think the slot for the accelerator pump wears out.  I dremmeled the place where it hit the body and it's better.  Been contemplating the UN2's myself, but I need two.

[38plymouth]

I don't know if it's because the shaft is wearing on this thing or what but after the car sits for a little bit the shaft sticks and the only way to fix it is to disassemble the carb and pull out the shaft and scrub it clean with scotch bright. I'm done dealing with it. Three of the screws that hold the top down are stripped and have nuts and bolts in them and I'm just over this worn out carburetor. Would really like to hear from somebody who has actually used this new carburetor. I am not going to be fixing the old one anymore.

[Los_Control]

I vote @38plymouthtry's the carburetor and report to us it's value  

 

I have seen some reviews on other aftermarket carbs, honestly they were not that bad.

$300 in todays inflation actually seems fair ... I would think it worth the gamble .... no idea where it is made .... are rebuild kits available?

 

https://daytonaparts.com/m/replacement_carburetor_chevy.html

[desoto1939]

did you ever check the throttle saft idel dog?  This is used on my 39 desoto and would also be used on your carb. On the bottom of the carb where the linkage connects to the throttle there is a stud and on this is mounted the throttle iddle stop dog. This control the sisson chock and also the trottle speed. there is a set screw to adjust the throttle rpms and this screw then makes contact with this dog. On mine which was the original carb had worn a hole in the throttle shaft dog and was causing the rpm's to stay high and make the throttle sick.

 

Refer to my earlier posting of the pictures of the throttled dog.  There are couple of these throttle shaft dogs listed on ebay. I replaced mine and this also help with my issue of a sticking throttle and not being able to get the rpms down lower.

 

1939 40 41 42-52 Plymouth DeSoto Chrysler Dodge MoPar Carb LINK Fast Idle DOG

AMS Obsolete-Formerly Mitchell's

• (80397)

• 99.7% positive
• Seller's other itemsSeller's other items
• Contact seller

 

Rich Hartung

desoto1939@aol.com

Edited August 20 by desoto1939

[Semmerling]

There are obviously a whole host of reasons. But I'm going to suggest the following. If you, like many other people, are finding that you can get out and go to the car and gently press the on-carb actuator lever just the slightest bit towards idle set and it settles right down then the following comes into play. Your carbs have to be generally clean, your linkage has to be generally clean and lubricated, and if all that is the case then this....

 

 

[Plymouthy Adams]

when you consider the spring and its tension at throttle speeds and the wear it will see as the tension builds at x position at x speed you can see the reason the bushing will wear in an elongated pattern thus resulting in a slight ramp on the bush to fully reset...thus the added spring tension....If you rebushed the shaft or renew the shaft if it also displaying wear, then the light spring will suffice for a general long use with no problems...but this is not to say that you will immediately start this process again on operation....go ahead and make it drive by wire....(you may need to go to 12 volts for this...lol)  

[Sniper]

The return spring is not on my carburetor. It's part of the linkage right where the pivot is on the head. So there's no tension per se on the throttle shaft

[38plymouth]

I have family coming into town for a week starting tomorrow so this is going to be put on the back burner for a bit. But I am almost positive I will be driving to New Smyrna Beach in a few weeks and buying that carburetor. I am not going to try to fix that leaking, stripped out, worn out ball and ball ever again. I have had that thing apart dozens of times over the years and I am done with it.

[JBNeal]

is that soon-to-be-retired B&B gonna be put on a display shelf, like a trophy? 🏆

[38plymouth]

37 minutes ago, JBNeal said:

is that soon-to-be-retired B&B gonna be put on a display shelf, like a trophy? 🏆

It will be put in a box with every other original part that I have taken off or replaced. There aren't many parts I  the box but I believe in keeping everything so I can pass it on  with the car someday. Who knows maybe someday I'll try to restore the carb to like new condition. But for now I want something that is going to work good that I don't have to mess with anymore for a while.

[grea235]

I live about 30 minutes north of Mike's Carburetor.  I went down yesterday and bought two.  I have a dual offenhauser manifold.  They fit ok, same fuel line fitting, same air filter input size as a D6A2, which is what I am replacing.    Throttles spring closed, not open.  Biggest thing so far is the clockable throttle lever is either straight up and you don't get enough throw, or leaned back toward the fender.  I need to extend my throttle linkage.  I'll post a new thread when I get them sorted out and fired up.

[38plymouth]

17 hours ago, grea235 said:

I live about 30 minutes north of Mike's Carburetor.  I went down yesterday and bought two.  I have a dual offenhauser manifold.  They fit ok, same fuel line fitting, same air filter input size as a D6A2, which is what I am replacing.    Throttles spring closed, not open.  Biggest thing so far is the clockable throttle lever is either straight up and you don't get enough throw, or leaned back toward the fender.  I need to extend my throttle linkage.  I'll post a new thread when I get them sorted out and fired up.

Thank you. How does the choke cable fit? I'm concerned it won't reach and I'll have to find a longer cable.

[grea235]

I used a square to measure my old D6A2 and then the UN2.  I tried to keep it on the same plane as the center of the barrel.  The pictures don't quite show it well, but I have the differences.

 

This is the D6A2, obviously.

 

 

 

This is the UN2

 

 

Relative to the base, the location of the choke holder on the UN2 is 3/4 inches shorter and 3/8 inches inboard, so your cable will need to be 3/8 inches longer.  The throw of the choke lever itself is about 1/8 farther inboard and has a lot shorter throw.  The whole carburetor is 3/4 inch shorter.  The base flange is about 1/8 inch thicker.

 

My car came with a rusted up Sisson choke and a D6H2, so when I replaced it with the D6A2, I had to get an aftermarket choke cable, which by the way, fit too loose in the holder, so I had to put a copper tube sleeve on it to make it fit tight.  I don't know the diameter of an original choke cable, so I don't know if you will run into that issue.

 

I can get pictures of the throttle lever positions if you want.

 

 

[grea235]

If it helps anyone, here's pics of the UN2 throttle lever.  Closed and open in two different dimple positions.  I had to use the 2nd dimple position otherwise it hit my dual throttle linkage bar when it goes full open.  Between the two holes would have been perfect.

 

1st position closed

 

 

1st position open

 

 

2nd position closed

 

 

 

2nd position open

 

 

[grea235]

Update - I put the UN2 carbs on and got the linkage sorted.  I left the adjustable main jets alone; the instructions said they were preset.  Tweaked the air mixtures with a vacuum gauge and synched them up with a Unisyn.  It runs very well, idles nice and part throttle is great.  Way more driveable.  Starts up easily.  I do have a return spring on the linkage.  I'm adjusting it to get the least pressure on the pedal and ensure the carbs return.

 

I don't know how functioning dual ball on balls run; mine were cobbled together from 6 different carbs and I got tired of fiddling wirh them.

 

I am very happy with the new UN2's.

[Sniper]

Yeah that's the problem with most of our stuff they're wore out sometimes news the best way to go. I do have a question about the preset though preset for what? Might not hurt to consider fine-tuning those adjustments

[grea235]

I pondered how they preset it and to what flow.  They are running fine so far.  It's not loading up on gas or starving or hesitating, starts fine when it's hot.  I'm going to pull the plugs, clean them off, then recheck them after it's been run for awhile to see if it's lean or rich.  If either, I'll adjust the mains.

[38plymouth]

I drove up there yesterday and bought a carb. Spent 45 minutes with the owner and he gave me all kinds of advice. I got home and in 10 minutes I had the new carburetor installed and the idle mixture adjusted close enough that the car had run better than it had in a very long time. I still have to do a few adjustments to the linkage. Once I get it set correctly and have a chance to drive it I'm going to start a new thread on these carburetors. So far I am extremely impressed. The owner asked me exactly what car I was putting it on and he said he adjusted it for my car. He said I should not have to touch the main jet adjustment at all.

[grea235]

That's good.  I'm glad it's working for you.  Been driving mine with the duals and it's been running great.