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carter ball and ballcarb loading up at idle


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Hi, 

i have been struggling with the carb on my 34 Chrysler,. it loads up at idle, making it too rich to run without cranking up the idle screw.

My feeling is that there must be an internal crack in the main body. I have some extra carbs around. Tried swapping bodies around with no success.

I don't know anything about the history of these carbs, or if they were any good in the first place. Took the carb off my 38 Dodge (same type) and tried it, no problem, ran great! Wondering if this is a common problem with ball and ball carbs... anyone out there has any experience or suggestions with this? Thanks so much,

Greg

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The first thing I would do, assuming the engine is not prone to backfiring, is make sure the choke is all the way open and then put on some safety glasses and stare down the throat at hot idle. Can you get it down to slow idle but just too rich? At that point all the fuel the engine gets SHOULD be coming through the idle circuit where you cannot see it. If you see it dribbling out of the main discharge tube, or really anything up where you can see it, you need to investigate why. The most likely reason would be the float bowl running over. The most likely causes for that would be: 1) Float set too high (check float level setting) 2) Sunk float (hole in float, gas inside, dunk float in hot water and look for bubbles.) 3) Bad float valve (needle not sealing on seat, the old ones with a metal tip were horrible for this) 4) Fuel pressure too high (wrong fuel pump or electric fuel pump with too much pressure).

 

I don't recall ever seeing a cracked or porous body causing a problem like that, but it's been a long time since I have worked on one. Anything's possible I guess. @carbking could probably answer that. Good luck and let us know what you find out.

 

 

Edited by Bloo (see edit history)
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They were NOT good carbs, even when new. Chrysler design, built by Carter.

 

They were so bad, Carter thought it necessary to publish a troubleshooting guide to attempt to help customers, and minimize complaints:

 

Chrysler Ball & Ball carb troubleshooting guide

 

Of all the carbs Carter ever produced, this was the only one they thought needed a troubleshooting guide.

 

(Opinion) the first decent Ball & Ball downdraft was built in 1939. Carter felt the same way, as in 1939, Carter released service replacement carbs for the 1933~1938 carbs.

 

Jon.

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Hi Fellows,

Thanks so much for your replies and input. I am sure we have no mechanical issues, as both cars run properly with the one decent carb. 

The float and float level seems to be good, I have removed the top of the carb while it was running and held the float to let the level drop.. no difference. 

just ended up stalling when the level got too low. Fuel still dribbles out of the main discharge tube. This leads me to believe there is an internal crack?

Jon, as the carb guru, have you ever seen this? You say these units are poor, can you suggest a substitute? I think these cars both were originally

equipped with Strombergs...?

Thanks again,

Greg

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If it is dribbling out the main discharge that REALLY sounds like float or float valve trouble. I'm not that surprised it stalled. How could you possibly know whether the idle jet was set close with the main discharge dribbling like that?

 

If you are sure... well..  It has been way too long since I have been in one of those, but it has to be mixing air somewhere on the way from the bowl to the main discharge tube. Maybe whatever hole lets the air in is plugged and the gas is siphoning? Does it have a bowl vent? Could that be plugged? Or maybe misadjusted if it is the type that moves?

 

A crack or porosity would have to be in a certain location for the gas to get from the bowl into the main discharge, wouldn't it? With it stripped down you should be able to see where the passages go. Any that are not obvious could probably be sussed out by shooting brake clean through the passages (don't get it in your eyes!). Once you know where the crack or porosity has to be, couldn't you fill the stripped down bowl with gas or paint thinner or something, and look for it to seep out of whatever passage has to have the crack or porosity? If I really suspected that, I would be looking for a way to prove the casting is bad.

 

My money is still on the float or float valve., but I guess I'll wait to see what Jon thinks.

 

Edited by Bloo (see edit history)
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As a passive observer.......and having never touched one of these carbs.........if Jon says they were junk when new, I would go with a replacement he mentioned in his post. 

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Thanks again, yes, I am anxious to see what Jon says. With that much fuel dribbling in, of course the the mixture screw had no effect. I was concerned about the float level. With the top off the carb and the engine running, I was able to hold the float up and shut the needle valve . This eventually lowered the float level, but did not alleviate the problem. My belief is that there is an internal  crack in the housing that I can't see... 

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I don't have any books I can get to that cover 1934. I have a Motor and a Chilton that cover 1935 and 1936 respectively, which I believe is very close to the same version of the BB. Both have drawings (different ones) showing the main discharge circuit. Maybe they are not to scale, but they sure look like they are. They show the discharge nozzle at the same physical height as the edge of the fuel bowl, making it appear physically impossible for this to happen, crack or no crack. Not being there to look at it makes it awfully hard to tell. The only area where there appears to be a common wall with the fuel bowl is right above the main jet. It certainly appears that if there were leakage, the gas could bypass the main jet making the mixture too rich, but still should not cause dribbling at idle. Are you sure the gas that is dribbling is coming from the main discharge in the venturi? Could it be coming from somewhere else?

 

If there were a crack in the main passage where it sticks out into the throat on it's way to the venturi, that would dribble gas for sure, but it would dribble out the crack, not the main discharge.

 

 

Edited by Bloo (see edit history)
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