Pre-war (up to 1942) Problem with Carter 423s Carburetor

[Brad Ipsen CLC #737]

One other thing.  Looking through the Buick cut sheets they don't have the part number for the cover just like the LaSalle but they do have the gasket listed for the cover.  On the LaSalle it is part number 121-63.  This matches the Buick gasket number for models 419S, 440S 448S, and 474S.

[39LaSalleDriver]

Apologies for my delays in responding to this thread, but real world work issues got in the way. However, I have not been idle.

This morning I had an extensive conversation with Jon, the owner of the Carburetor Shop in Eldon, MO. Turns out he may well be the foremost expert on Carter carburetors around. Seems when Carter got bought out several years ago, he had the opportunity to buy out all of their archives to include blueprints, some machinery, etc. Apparently he was a Carter dealer/distributor back in the day and had connections within the company.

According to him, the 423s was a one off production model, and has a high percentage of confidence that bowl covers from other models will not work for one reason or another. He wouldn't commit to a 100% chance that no others would work, but indicated that if they did it would be a sheer luck proposition. Personally, I have no desire to buy upwards of 10 different model carburetors to only find out that none of them will interchange.

His suggestion for a repair was to rethread the hole with a ever so slightly larger, custom made die and plug. Apparently the older threading is slightly different (smaller) than modern threading and in theory could be done. I know that I have neither the skill, knowledge, nor equipment to accomplish such a task. And quite frankly, I don't know that I would trust a machine shop to accomplish what I want unless I was standing over their shoulder giving specific instructions. I feel as though what few times I have jobbed something out to someone, they invariably don't follow my instructions and/or cut corners, leaving me somewhat unsatisfied with the end result. 

For now, I have the Marine Tex epoxy on there holding it together which I expect will give way within 3-4 weeks time. When and if that fails, I have been investigating (and bought) a Muggy Weld kit. They claim that it will solder materials such as pot metal and brass together. With the reviews and videos I have seen regarding their product, it looks like a very promising solution.

I think on the next attempt I will use the Muggy Weld to sweat the plug to the bowl cover. Granted the repair, if it works, will be semi-permanent; but there again, I really don't have a need to remove the plug to access the screen underneath. Perhaps in the near future a 423s carb will present itself and I can execute a proper repair/replacement.

[LaSalle5019]

What about tracking down 460 and replacing your entire carb? My other suggestion is putting on the Stromberg AAV-26 but that'll require some work on plumbing.  Made that suggestion in the AACA forum.

[39LaSalleDriver]

While I appreciate the suggestions, I fear I have spent far too much time, money, and effort over the last four years keeping my car as original as I can to give up on my 423s. I have no real reason to doubt it is the same carburetor that my car left the factory with, and I'd really like to keep it that way until it gets to the point that there is absolutely zero possibility of using it or finding another 423s. I won't say "never", but until I've exhausted every possible solution or workaround, I'm sticking with the one I brought to the dance.

I could be fooling myself, but the more I've looked into it the more convinced that the Muggy Weld solution will more than satisfactorily serve my purposes. I know there may be doubters, naysayers, or those that are completely ignorant of this system, but I am willing to give it a banty rooster try. There's some fantastic YouTube videos out there of carburetor repairs that guys have achieved with Muggy Weld. Certainly some with far more extensive damages than I have. In order to hedge my bets, I've also picked up a cheap, junked out Carter carburetor from the same era which should in theory be metallurgically identical for practice purposes. I'd like to get a feel for melting points, technique, etc. before I go taking a torch to my real carburetor.

As mentioned, my first approach will be to sweat the brass plug into the threads (or more like what remains of the threads) of the pot metal bowl cover. If I can get that capillary action going to pull the solder down in there and hold it all together, I think it should cure the situation.

If that doesn't seem to be working, my next thought is to make either a brass or aluminum disc to fit down into what is left of the threads to form a shelf or platform if you will for the solder to rest on leaving the hollow chamber below. I can then backfill the top with the Muggy Weld solder and effectively form a permanent plug. Then grind and shape it flat on top, and JB Weld a brass hex made from my spare plug on top to complete the illusion. I am perfectly aware that this will eliminate the functionality of the brass plug, but again, I'm running two fuel filters plus the sediment bowl...that mesh cylinder under the plug is superfluous at this time anyway.

I know there are probably some people rolling their eyes at this plan, and I get it. It's not my ideal solution either. But sometimes you have to get creative with solutions when faced with a seemingly unsurmountable problem. I'll be sure to report back with the results when I get everything satisfactorily resolved or destroyed. 

[Lexi]

I was hoping Muggy Weld might work, hence my earlier post. I actually have some sticks of it here but never tried them on carburetor metal. So let us know how this works. So my disclaimer is I am not sure if it is right for you but I think there is a good chance that it will be, as a last resort. I also follow your logic and it makes total sense to me, especially practicing on another, similar scrap piece, to get a feel for using this brazing medium. As an after thought, prior to sweating that brass plug, etc., if the melting point of that period junkyard Carter is dangerously close to the Muggy Weld, you may wish to consider wrapping the exterior of your carb with an ice cold, wet rag to hopefully stave off any outer shell deformation during heating. Might help. I know plumbers will wrap soldered joints with a wet rag where there is a possibility of one melting when heat is re-applied for another nearby repair. Good luck USNTar. Clay/Lexi

[39LaSalleDriver]

if the melting point of that period junkyard Carter is dangerously close to the Muggy Weld, you may wish to consider wrapping the exterior of your carb with an ice cold, wet rag to hopefully stave off any outer shell deformation during heating. Might help. I know plumbers will wrap soldered joints with a wet rag where there is a possibility of one melting when heat is re-applied for another nearby repair. Good luck USNTar. Clay/Lexi

I'm already ahead of you on that!  Exact same thought crossed my mind. I see Muggy Weld also sells a product like a granular goop substance to help shield irregular shaped objects, but I figured I'd try the plumbers trick first. Looking into it, it would appear that pot metal melts at about 750 degrees +/- depending on the alloy composition. The Muggy Weld melts at 350 degrees +/- so I shouldn't have to get it so hot. I think the trick is really going to be in the torch technique and not concentrating the heat so much in one spot. That's why I figured on practicing on a junker so I can get a feel for how far away to keep the flame and how quickly I need to keep it moving. Most likely I'll have the missus off to the side shooting constant temperature readings with a laser thermometer just to be on the safe side. Also I gather that one of the most important things is to clean up the area to be soldered immediately before working on it. Not the night before, not an hour before, but immediately. Seems that oxidization from air exposure starts fairly quickly and can cause the repair to fail.

[Lexi]

That's awesome news Jon. Yes, some metals oxidize rather quickly. I think aluminum is another, though it forms a protective coating very rapidly to help preserve it. As in all welding and soldering type jobs, cleanliness is important just prior to applying heat. You want the best adhesion possible. Keep us posted and best of luck in your repair! Clay/Lexi

[39LaSalleDriver]

Over the weekend my Muggy Weld starter kit and the junked out Carter WCD carburetor for practice purposes showed up in the mail.

I am absolutely delighted to report that I have no doubt the Muggy Weld repair will cure my problem. Preliminary testing on the junk carb showed that it is not scary in the least to use. Just keep the torch moving and dipping the rod with flux along the point where the pot metal and brass plug meet does the trick. At no point was it ever in danger of overheating and melting the pot metal, though I'm sure I could have done that should I have tried. I make no claim to be soldering expert, so some cleanup of excess solder will be required, but the important thing is it is rock solid and impervious to gasoline exposure.

Now I'll wait until the Marine Tex softens up and breaks down on the 423s then I'll go ahead and pull the carb one more time to execute the solder repair.

Meanwhile, I'll still be keeping my eyes out for a spare 423s to have on hand for parts, etc.

[Lexi]

Yey! That is fantastic news Jon! Clay/Lexi