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

[39LaSalleDriver]

Ever since I got my 39 LaSalle, I've had a minor problem with my Carter 423s carburetor. I had it rebuilt three years ago, but the problem persisted. Today, it finally has gotten to a point that I have to find a permanent solution.

The problem is that on the top front (what I believe to be called the Bowl Cover) is a chamber where the fuel line enters from the drivers side. Inside the chamber resides a small screen wire cylinder which presumably strains the gas flow. The chamber itself is sealed with a 3/4" diameter, brass plug. That plug has become my problem. When running, gas seeps out from the plug and drips down the carburetor body. One can imagine the danger that poses. At first, it was barely noticeable, but has gotten worse with time.

I only really noticed the seepage after the carburetor was rebuilt, but it may well have been there before. Originally I tried snugging it up a bit to resolve the problem. That worked for a while, but reappeared. Then I used Gasoila sealant, but eventually that gave way. Today I decided to reapply more Gasoila and observed that now the threads in the bowl cover have stripped out and I can no longer keep the brass plug in position.

As a result, it is really too unsafe to try and operate it in this condition. What I'm wondering now is if it would be feasible/possible to retap the chamber or possibly helicoil it? Since I run a fuel filter on my fuel line by the tank, in theory, that chamber doesn't really need to be accessed by me to clean the screening. Perhaps some sort of JB Weld or epoxy permanently affixing the plug would remedy the situation? The only other option I see is finding another carburetor and pirating the bowl cover off of it to put on mine. Does anyone have any other suggestions that I'm not thinking of?

[Lexi]

When I removed my old Rochester 4GC for a rebuild, I had a tough time removing the large brass fuel line inlet nut. It was in there rock solid and I could not believe the force required to break it loose. I determined that a previous owner had experienced fuel leakage there due to worn threads, and then used a sealant to lock them on re-installation. Looked like JB Weld to me and it must have held for many years. I went through 5 carbs looking for various parts and found that stripped gas inlets and worn threads there were a common problem. If you can helicoil it, great, (I got away with a helicoiled bowl screw thread also). If not you might try looking to see if the bottom threads are OK. If so, you may be able to locate a fitting with extended threads that might grab and save the day. All you need is an extra turn or so. These "extended thread fittings" used to be around for cars like mine, albeit for leaky inlet ports. Not sure what might be available for yours. Probably best to speak with an old carb guy and see what he may have. Sadly, these are common problems. If all the threads are indeed stripped, you might get away with locking it in place with JB Weld. I had to use it to seal a leaky well plug on my carb and it has lasted for 7 years and counting. Would still want to explore a more permanent and arguably safer repair for your problem with a professional first. Clay/Lexi

Edit: Not sure if I was clear. Your present brass cap threads may not reach where the final carb threads are cut. That is why I suggested to see if the bottom last 1 or 2 threads there are OK. They may be untouched. The fuel inlet fitting with extended threads have only a slightly longer reach. Even though the part I am thinking of is designed to accommodate a fuel line, it may still work in your case. If one can be found to fit your carb, you could always find a plug to screw in the "top" to seal it closed, (as you won't be running a fuel line through it). Yes, it won't look 100% OEM, but at least you will be able to drive your car safely while you look for an intact bowl cover. Others must have run into this problem with this year of carb so it will be interesting to learn what they did. On a final note, I looked at a lot of 4GC carbs and parts and I noted that there were even slight variations in the length of the fuel inlet fittings! That's right, even they varied slightly in length. Some grabbed my bottom good threads, while some did not. The extended thread fix will only work if you have a thread or 2 left in good condition at the bottom. Mentioned for what its worth, as I realize your vehicle is older and a different set up carb wise. If no good threads left and you can't helicoil it, seems to me that plugging it permanently is the answer. Have a chat with your carb guy on that.

Edit 2: In my case I also did try another bowl cover from another carb, but found that it had "warped" under previous use and did not match well when mounted on my bowl. It leaked. Doubled up on the gaskets, then went with another carb. Something else to consider when looking for replacement parts

Clay

[fishnjim]

Looks like in the picture they put a copper gasket under the plug.   I'd check and see if it's the right part and thickness.  There's exploded parts diagrams for Carters.   
Some times you can't apply enough torque to seal copper, or it gets distorted, and the hole and OD size has to be correct.   If not copper, then the same applies for whatever they used.   If it's not the right thickness then the threads bottom before it seals.
You can add teflon tape to the plug threads or regular liquid pipe thread dope to help seal.   Check that it's not stripped first.   That's cast aluminum and won't take much overtightening.
Try to find another cover if this one is toast.

[Lexi]

Good point but he says the bowl threads are "stripped out". My earlier post was suggested in case one or two remain, deep and out of reach of the fitting. If those threads are there, he could tape it, but he still has to reach them, hence my earlier post on a possible repair. I wouldn't use regular white "Teflon" tape as gasoline eats it and may cause worse problems. The so called gas fitters yellow tape can be used as far as i know, but best to research this. If there is a washer there, changing or removing it may provide extra penetration to reach any possible remaining threads. Then we are back to using a sealant at the top like JB Weld, & perhaps gas fitters tape for any possible remaining threads.

If there are no remaining useable threads then it seems to me that a home fix is restricted to a helicoil thread repair or plugging that fitting permanently (and removing the screen) with input from a carb rebuilder.

Clay/Lexi

[39LaSalleDriver]

Thanks for your input guys. One thing I didn't mention was that last night I picked up some Permatex Motoseal to put on the threads to see if that would help. Figured worst case scenario it doesn't, and I could clean it all up and try something different. No harm, no foul. Well, checking it this morning...it didn't work...not that I was surprised.

I then decided to go ahead and pull the carb off the engine so I could get an up close look at what was going on. Carb could stand a good cleaning anyway. As expected, the threads are shot. Oh, there's a couple deep in as Clay suggested, but I would be dubious that they would fare any better even if I had a plug long enough to reach down there. To Jim's point, yes, there is a fiberous washer on there, but removing it doesn't really give me any advantage. The threading on the plug is just too short, and the threading in the cover is too hogged out to make any meaningful difference. As it is, the plug just sits in there with only a small bit of friction right now.

So far as my pea brain can noodle through (and my abilities will allow), I'm back to my three previous options:

1) Best permanent solution -- find a new carburetor and replace, or get a junked one with a good bowl cover to put on there.

2) Best temporary solution -- use JB Weld (TankWeld?) and epoxy the plug back in there. Suspect this will be a irreversible repair if it holds up. If it works, great. If it doesn't, I'm pretty much back to option 1. I feel fairly confident it can do the job, but my only concern is how well it will hold up to exposure to gasoline. Guess I'd have to try it to find out.

3) Questionable solution -- tap it out to accomodate a larger plug (if I can find one) or helicoil it (if I can find one big enough). I'm not real wild about this option as I think it will eventually take me back to 1 or 2. I don't have a lot of confidence in the strength of the carburetor body's ability to hold new threading.

At this point, unless someone else has some better ideas that I would eagerly love to hear, I think I may shoot for a combination of 1 and 2. Try the JB Weld route and hope for the best. If it holds up that's fantastic...but I'll still keep my eyes out for a spare parts carb. When and if I do find it, then I can salvage the bowl cover and put it on my carb and still have spare parts for any other situation that may arise down the road.

[Lexi]

Any idea what thread size it is? Being able to grip even one or two threads may be key, as there are 2 issues; 1) you don't want it coming off 2) you don't want it leaking. Speaking from experience, one or 2 turns may be all you need. But do keep us posted! Clay/Lexi

Edit: Just to be clear Teflon is a trade name. The gas fitters tape I referred to, as well as the so called Teflon tape used by plumbers, are all PTFE (polytetrafluoroethylene) based products. A pipe fitter years ago advised that the "gas fitters" tape is more resistant to chemical attack and he indicated that there were several degrees of purity among such PTFE tapes. Also the white plumber's Teflon tape is lightweight and more prone to shredding than the gas fitters type. That is why it wraps so well around pipe threads and ends up looking like stringy mozzarella cheese. The down side is that no one wants to have shards of shredded tape moving through their carburetor.

[Daryl Chesterman]

May I suggest calling Daytona Parts or Mike's Carburetor, and tell them about the problem.  They may have run across this problem in the hundreds of carburetors they have rebuilt.  I have personally dealt with Daytona, and they are very knowledgeable and willing to help with a problem.  You could even email the picture to both places and ask for their input.

Daryl Chesterman

[LaSalle5019]

I have not had good luck with JB Weld and fuel. It tends to get soft and fail. I suggest Marine-Tex.

[las39]

Carb is made of pot metal. I wouldn't use any chemical sealant. I'd carefully brass or tin solder threads and rethread.

[39LaSalleDriver]

As a follow up to this, last week I proceeded with the plan to use JB Weld. I had read many conflicting ideas on whether JB Weld would hold up for any period of time, some say it will, others say it won't. I guess I'll find out, but I'm hoping that since it technically won't be "immersed" in gasoline, it will potentially have a higher success potential.

So far, so good. After allowing it to cure, I've put the carb back on the car and it seems to be working exceptionally well. Will it still be six weeks from now? I don't know. I'll cross that bridge when I come to it. If it does fail, I may next try the Marine Tex as Scott suggests.

[Lexi]

Great news and nice to get follow ups. I know what you mean by JB Weld reports being all over. I have had success with it myself. I would imagine following its directions for use would significantly affect results, (especially care when mixing). Just keep an eye on it and lightly touch with your fingers to check for any sweating of fuel, visually or odor, as it is not likely to fail all at once. My leaky well plug has been fine for almost 8 years after a JB Weld repair. Still check that repair from time to time. Clay/Lexi

[fishnjim]

Here's a WDO service manual.   Slide 25 calls for a gasket under the strainer retainer.   
I don't have a WDO part list but they're available for about $10 from the carb places.
I suspect, if the threads aren't stripped, it probably is the wrong gasket after rebuild. 

The problem with JB Weld is if you have to take it off again...   JB Weld makes a putty specific for gas service as "Tank Weld".   It sets up rather quickly.   Regular pipe thread dope(not teflon) would probably be as good and removable.

[39LaSalleDriver]

Just keep an eye on it and lightly touch with your fingers to check for any sweating of fuel, visually or odor, as it is not likely to fail all at once. My leaky well plug has been fine for almost 8 years after a JB Weld repair. Still check that repair from time to time. Clay/Lexi

That's precisely what led to my discovery of this problem. I had been watching it for 2-3 years now and adjusting as necessary. I definitely will continue to keep an eye on it. Like you, I suspect it will be a gradual failure if it fails at all.

Here's a WDO service manual.   Slide 25 calls for a gasket under the strainer retainer.   
I don't have a WDO part list but they're available for about $10 from the carb places.
I suspect, if the threads aren't stripped, it probably is the wrong gasket after rebuild. 

The problem with JB Weld is if you have to take it off again...   JB Weld makes a putty specific for gas service as "Tank Weld".   It sets up rather quickly.   Regular pipe thread dope(not teflon) would probably be as good and removable.

First off, thanks immensely for those scans from the Carter manual. I suspected for a long time that something like this was out there, but I had not run across it.

Your caution about JB Weld is duly noted and I considered that before applying. I wondered about the "Tank Weld" but after reading so many comments about it via various forums and reviews, I have developed the suspicion that it is the same as the standard JB Weld, just in a different form that can be molded to surfaces that may not be conducive to the normal semi liquid version if it were applied.

[Brad Ipsen CLC #737]

Be on the lookout for a parts carb.  Should be out there and most likely doesn't even have to be the exact one for that part to interchange.  It is a paper gasket under that fitting at least the Carter carbs I have.

[39LaSalleDriver]

Following up here...

After nigh on two weeks and say 75 miles of driving I can definitively say that my JB Weld solution has failed. Despite reading many comments in various places that it would hold up to exposure to gasoline, in my case it did not. Took car out to dinner last night and checked on it after getting home. It had begun oozing out from the plug and had the consistency of taffy. On the good side, at least it didn't damage anything to try. Next step is to try Marine Tex though I am doubtful it will do much better. In conjunction with that I have placed an ad in the WTB section here looking for a parts carburetor so I can make a permanent, proper fix.

If anyone has any ideas on what carburetor body parts will interchange with the 423s I'd really appreciate knowing so I can expand my search. Thanks.

[Brad Ipsen CLC #737]

I would start with Daytona Carb in FL.  They may even have a parts core.  They have Carter drawings from previous discussions.  Should be able to find this part.  It is not a part that normal fails.  Looking in my Carter books 40 LaSalle and 40 Buick look the same.

[39LaSalleDriver]

Have reached out to Mike's and Daytona, but had no luck. Daytona did turn me on to the possibility that a 460s, 506s, or "Buick WDO"  (presumably a 419s, 440s, 448s, 474s) bowl cover "may" work. Because of their hours, I'm going to have to wait until the first of next week to contact The Carburetor Shop to see what they may have.

If I knew for fact that a cover from a 460s, 506s, or "Buick WDO" would work, I have no problem buying one of those. However, I am hesitant to drop potentially $100+ on something that could become an expensive paperweight when "may" turns into "doesn't".

For now, I am falling back on trying another repair using Marine Tex rather than JB Weld, but I have no strong faith that it will work any better. If it does fail, I am probably going to proceed to try using a helicoil repair with the hope that a correct bowl cover may pop up somewhere soon.

[Lexi]

Sorry to learn that JB Weld did not work in your case. Looking at your photo you do have some threads left at the bottom, (and as you previously indicated). A trip to a carb rebuilder who has lots of cores laying around, and parts, may have a newer fitting that due to a slightly longer reach, may grab those bottom threads. Still something to consider if helicoil does not work out. If you can get a longer fitting, that plus a couple of wraps of gas fitters tape, (the stuff in the yellow package), might work. Not a big fan of using sealing tape on fuel fittings, but this might do it and it is far less prone to shredding than regular Teflon tape. When all else fails and you have determined that your bowl top is indeed a paper weight, perhaps look into a permanent repair using "muggy weld" to braze the existing fitting on for good. Carb will have to come off and be cleared of fuel and vapor first. Anyone out there ever used muggy weld to fix a carb? Product is supposedly used to repair a lot of vintage car "pot metal". Just a thought. Clay/Lexi

[Brad Ipsen CLC #737]

Looking some more in my Carter cut sheets (for the lack of a better word) I now think the Buick one is different. It has the same gasket and fuel inlet layout but Buick didn't need the bowl overflow pipe.  On the other hand I have seen other covers that did not have it but they had a ring cast in where it goes.  It was just a drill and tap at the factory on the same casting.  On the back side of the cut sheets they list all of the parts except the cover you need and the main body.  I guess the reason is if you need those parts you were supposed to buy a new carb.  The 40 LaSalle with the 460S looks identical in the picture and on the 423S cut sheet they say the 460S carb supersedes The 423S.  There are a lot of 40 LaSalle's around so there is hope there.

[39LaSalleDriver]

Looking some more in my Carter cut sheets (for the lack of a better word) I now think the Buick one is different. It has the same gasket and fuel inlet layout but Buick didn't need the bowl overflow pipe.  On the other hand I have seen other covers that did not have it but they had a ring cast in where it goes.  It was just a drill and tap at the factory on the same casting.  On the back side of the cut sheets they list all of the parts except the cover you need and the main body.  I guess the reason is if you need those parts you were supposed to buy a new carb.  The 40 LaSalle with the 460S looks identical in the picture and on the 423S cut sheet they say the 460S carb supersedes The 423S.  There are a lot of 40 LaSalle's around so there is hope there.

Thanks Brad, I think you and I are pretty much on the same page here. I too have noticed that certain models have the ring for the overflow fitting, but weren't drilled and tapped. I should be able to do that easily enough. Tim? at Daytona also suggested to me that the 460s should be a direct replacement and that the bowl cover should work perfectly. He was a tad more vague about the Buick models only stating that "Buick WDO's" should work, but didn't mention specific numbers. My own research has turned up the above listed models which I think he was referencing. It appears that there are far more Buick carbs available than LaSalle's, so I will probably go that route if I can't source a cover from The Carburetor Shop. I don't see a lot of chatter about them, but their website implies that they have hundreds if not thousands of carbs on the shelves for sale and/or parts. I guess I'll find out when I call them Monday.

At this point, I think the Marine Tex repair should hold up at least for a couple of weeks if not longer to get me by. However I really think finding the proper part is the best solution. I have determined to probably not pursue the helicoil route. By the time I go to Grainger and purchase the correct tap, drill bit, and inserts, I'll probably be well over half way to the cost of a replacement carburetor.