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AVS619

Operation with Updraft Carburetor Question

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For those of you with brass era cars with updraft carburetors, when shutting off after running either for a short time or a long drive, is it typical/normal for there to be eight to ten (maybe more) drips of gas to leak out? I find that occurs on my 1909 Regal with the original Schebler Model R and even with a new universal Zenith I put on. Is this something to be concerned about and is it a safety issue? I hope to take the Regal on some tours this year. Please let me know of your experiences driving your brass era car with an updraft carburetor. Thanks. Tom Edfors. edfors@charter.net

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It is normal operating procedure for many with brass era cars to shut off the gas at the tank after stopping the engine. Pressurized tanks should be "blown off" to relieve their pressure. If you have a fuel pump the system may still be pressurized due to air in the system and a second shutoff at the carburetor may be in order. This also applies to carburetors with less than perfect float valves and gravity flow. Any gasoline drip or leak is something to be addressed, fire is a big issue with these cars.

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Perhaps some more information would be of help. My original Schebler Model R is not working (anyone have a functional Model R for sale?) so after some advice I purchased a Universal Zenith (Model 12566) and mounted it using a four inch manifold adaptor. The carburetor sits low almost to the bottom of the engine. Fuel feed is gravity. After installing it, and seeing the fine print of the instructions, it is designed to leak out fuel that condenses on the manifold walls. There is a drain at the bottom. It makes the motor run well, better than the Schebler did, but when I shut off the engine, there is quite a lot of gas that leaks out. I guess this answers my question about leaking, it is normal for the Zenith. Now the question is, can an adaptor or reservoir be made to capture this fuel safely so that it does not leak upon the ground. If so, can someone tell me (provide directions) and how to make one? I need to solve this somehow soon as I have promised to be on a tour in later May with this car. Any help will be greatly appreciated. Thomas Edfors. edfors@charter.net

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I think the post-shut-off drips you are describing are normal providing the drips stop after a short amount of time. If they continue to happen after the vehicle has been shut off for awhile, it is not from condensation or unused fuel, but more than likely from a leaking needle/seat assembly which could be caused from a minute piece of dirt getting into the carburetor. As a safety, you should have a fuel shut off next to the fuel inlet at the carburetor and make a practice of shutting the fuel off when the engine is not running. I would NOT make an adapter or reservoir to capture the fuel as it is better for the fuel to go on the ground since it will evaporate quickly (unless there is too much of it, or it continuously drips). A reservoir with a puddle of gas near a hot or running engine would be a dangerous proposition.

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If you have fuel condensing in that amount on the manifold walls you do not have enough carburetor heat.

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Thank you Layden B and Motoringicons for your input. Layden, how would I increase the carburetor heat? This new replacement Zenith sits an additional 4" under the original manifold as a manifold adaptor had to be used to get it away from the magneto. The bottom of this carburetor now is about at the bottom of the crankcase. That is why I considered a way to 'catch' the drips as anything and for that would be low and away from the engine and exhaust pipe and would even be cooled by fan air when the engine was restarted. I saw something like this back in the late 60's on a 1911 Maxwell but I did not take a photo and am relying on memory which is not always as clear as it should be. Anyway, it appears that a Zenith 12566 is deigned to leak up to 1/4 cup of gas (says so on the instruction sheet) which to me seems way too much and I am sure hotel parking lots and gas stations will not be happy with that much on their asphalt. I get a quick stream and then 10 drips every time the engine is turned off. If I could find a way to fix the original Schebler Model R I would put is back one but no one seems to want to touch this model Schebler. So assuming the Zenith will always drip gas, is there a way to minimize the amount that drips out? Other than that, anyone have a carburetor that will work on a four cylinder 201 cubic inch engine? Tom.

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Layden is right. Heat to the carburetor and/or intake manifold is very important on these early updraft carburetors. You can connect a flexible tube to the air intake on the carburetor and place the other end near the exhaust manifold or exhaust pipe so the air coming into the carburetor will be warm. Another common idea was to get copper tubing and wrap it around the intake manifold and plumb each end of the tubing into the into the coolant system so the hot water will warm the manifold.

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The original Schebler has am original flexible tube that took hot air from around the exhaust pipe for heat but, what I now have a brand new Zenith 12566 Universal Updraft and that is now what is on the car. I do not think a modern carburetor requires the heat the old one did. I think some of the problem may be the additional 4 inches of manifold. In any event, the amount of fuel that dips out is more than I am comfortable with even though the instruction sheet with that came with it states that up to 1/4 cup of fluid is to be expected. Anyone have a suggestion as to another brand and model of a replacement carburetor. Someone must have replaced there original carburetor and is touring with a more modern replacement. Tom

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It is not the carburetor that actually needs the heat but the air/gas mixture that needs the heat to fully vaporize the gas. Today's gasoline is actually less volatile than years ago. A carburetor makes small droplets from the jets while fuel injection makes a finer spray. Smaller the size of the gas particles in the air, the more surface area and thus faster and better atomization in today's cars with fuel injection. Today's gas has a higher boiling point to combat vapor lock, it gets very hot under the hood in modern cars.

All that said, 1/4 cup of gas on the ground under a tractor carburetor is a whole different ball game from gas dripping in your garage!

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Hello Layden. Thank you for continued input. I must admit this is a bit frustrating as I need to get the Regal on the road. I know I have a tractor carburetor, which was recommended by a few other car friends, but no one told me the amount of fuel it would leak. I found out after its installation. It does make the car run better however and it likes hills better. But the problem still remains. If I retain this Zenith, can I minimize or somehow stop the leakage? Otherwise, I have to find another replacement carburetor or find an original Schebler Model R (which I will advertise for). I understand the technical issues with carburetors but what I need now is a concrete solution that will get the Regal back on the road. By the way, the original Schbeler began to pour gasoline (not a float problem) and the usual carburetor rebuilders do not want, for some reason, to touch the Model R. After 103 years (it began it's problems last year) it appears to have broken somehow.

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As you stated "After installing it, and seeing the fine print of the instructions, it is designed to leak out fuel that condenses on the manifold walls." the source of the leakage may be just that, gasoline condensation. Try some intake air heated by the exhaust pipe or manifold and your problem might just go away and the engine may run still better as well! You indicated that the original Schebler did the same thing to some degree and I would bet that a change to another carb will not solve the problem.

These are from the 1914 Schebler carb catalog.

post-34894-143141876508_thumb.jpg

post-34894-143141876491_thumb.jpg

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Greetings Layden. The carb catalog shows one of each Schebler I have, the D is on a highwheel IHC and I have the L's on a '10 IHC J-30 and '12 Buick. The Model R on the Regal had worked fine until the original cork float broke to pieces on a tour. A new modern material float was made and installed and that is when the trouble began. While the carburetor would not leak when the gas was turned one (gravity feed) after the engine was run it would leak, no pour, gasoline out. This would happen every time with no leak upon opening the fuel valve, a good run of the engine and than gas pouring out the bottom. I have tried new floats, new needles, a new seat, etc to no avail. Other car people from the area (few for brass cars) have looked at it and said 'no idea'. I even contacted various carb rebuilders who said they wanted nothing to do with a Schebler Model R. Thus the purchase of the Zenith. I have found another Model R for sale (more than I would like to pay) but I am thinking I am just buying another old carb that eventually will have to be rebuilt. I'll try hooking up the Schebler's hot air tube (or make one) and see if that works. Thank you for your help. Tom

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Is the Schebler model R original to your car?

The earliest record we have of the Schebler Model R is 1913.

I would have expected that if your Regal originally had a Schebler, that it would be a Model L.

Jon.

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This has been a very interesting discussion but I am left with the same problem. I have taken the new Zenith off and put it on the shelf for a future project. Back to the Schebler, I'll have to make it work. I know not if it is original but it was on the Regal when I got it and the car was unrestored. The question I now have is, how does one adjust the float. Is there a technique? It may be the leaking after the engine is shut off simply may be a wrong adjustment of the new float allowing fuel to leak out the nozzle but it is hard to tell where the nozzle tip is within the brass body of the carb. I have adjusted many floats over the years but never on a Schebler R which seems different than the others. Any recommendations? Tom

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From what I remember of the Schebler model R, the float is NOT NORMALLY adjustable.

With many carburetors, the float may be adjusted by changing the thickness of the gasket pack under the fuel valve seat. In the case of what I remember on the R, the seat is machined in the bottom of the bowl, thus not adjustable.

However, one needs to sometimes get creative (with Scheblers, often VERY creative). Once can obtain different thickness of mylar, and cut a spacer to place between the float arm and the float pontoon. This should lower the float pontoon, and cause the float to exert its buoyancy at a lower fuel level, this helping to minimize leaking. HOWEVER, I would never consider turning my back on either a Schebler L or a Schebler R. In fact, I don't think I would ever leave one of these carbs on any engine that I planned to start and operate.

I have no specifications on the 1909 Regal, so do not know the displacement and the applicability of the Zenith 12566 (there are other Zeniths with the same bolt pattern and larger venturii); but if might we worth trying to get the Zenith running instead of the Schebler.

Jon.

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Hello Carbking. I would prefer to have a better Zenith carb on the Regal but where do I find one? The 12566 was all I could find and it too leaks. The instructions warn that it can leak up to 1/4 cup of gas, and it does! If there is another Zenith available that will not leak (a few drips may be typical) I would like to know where to get one. The tour is less than four weeks away and I have yet o find a solution to this problem. I am also a bit nervous that you say you would not use a Model R or an L as the other three brass ears cars I am getting back to life all have Model L's. I have been 'collecting' these early cars since high school back in 1967, when they were 'cheap' but with the economy we are in now, I doubt I could afford to buy three more carbs. I will have to make the L's work but they seem to be a better carburetor than the R. Quick note, the R on the Regal was fine, many miles of touring, and it did not leak until a new cork float was installed. It is much more buoyant then the original cork so it has upset the settings. The seat is indeed machined in, no adjustment there, so it has to be the float adjustment. Alas, where I live I am the only brass era car 'nut' so I am on my own. Thank you for help though, I do appreciate it.

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