1929 Model A leaking gas

cavalierhome

cavalierhome

Member
I just got my first model A.
When you shut it off, a few moments latter it starts leaking gas from the carburetor. The previous owner said that is normal and I should just shut off the gas valve.

That does not sound right to me.... Any help appreciated.
Cheers
Paul
 
I have owned Model A’s for over 60 years. In all that time, each time that I have shut off the car, I have turned off the gas under the tank. The few times that I have forgotten to do so. I have had a wet carburetor at best.

I my mind, just part of driving the car.

Enjoy.
 
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Welcome to Ford Barn!
Your carburetor should not leak after shut off. Any number of causes, float hanging up and sticking open, dirt in float valve, Bad float valve, incorrect float setting. You will need to disassemble your carburetor and check it out. After removing the float from the upper half of carburetor, shake it to see if it has gas inside caused by a leak. A gas logged float can't rise to shut off float valve. Sometimes light tapping on the outside of carburetor while still on car and leaking can dislodge a sticking float. Try that first before removing carburetor from engine.
 
I always shut off the gas and wait for the motor to stall before turning off the ignition. Two reasons: (1) prevent gas overtflow in case the float valve does not seal completely and (2) reduce corn meal buildup in the carburetor from evaporated ethanol gas.

That being said, it sounds like it is time to inspect/test your float valve and check the float level. Plenty of good information out there on dialing in these carburetors.
 
I haven’t shut the gas valve off for 5 months after fixing the carburetor float valve and installing a gas valve screen the one that’s in the gas tank.
 
Wow guys thank you so much for all the replies.
I will rewove and rebuild the carburetor, and hopefully that does it.
Where is the best place to buy the jets, shims, a float if I need it etc.?

Cheers
Paul
 
It may be best to send your carburetor, (I assume it's a Zenith?) to a professional rebuilder. I just remembered that an incorrect cap jet can cause the leaking you describe. It's not simple. I've heard good things about Berts Model A parts rebuilding Zeniths. There are several other Zenith rebuilders around the country as well that do good work. The aftermarket jets the vendors sell are too big and should be flow tested and redrilled. All very technical.
 
Ok I will start there, but ultimately I want to learn how to do my own work. I have never worked on a model A, but I did work on my race cars for many years and am pretty good around engines etc.

This is just a new adventure, I decided to start a little car collection, so far I have a 29 Model A, a 1986 Suzuki Samurai sitting in my garage.
 
The Zenith types were the OEM carburetor. They are made from cast iron and are relatively easy to ID.

The Tillotson model X or XF carburettor is an aftermarket unit that is very near the same function but is shaped a bit differently and is made from zinc die cast. There was also a round bowl Tillotson for the model A but they aren't as common as the model X.

Marvel Schebler also manufactured a carburetor for the Ford model A. It is also a zinc die casting and was sold under various rebrands like the Johnson JFA and Allstate 2405. These carbs work well but are a bit less common than the Tillotson carbs.

You will need to ID the carb to get gaskets or other parts but parts are available for all of them as far as I know. There is also rebuild information for all of them. You won't find an automobile carburetor that is much easier to rebuild than these.
 
rotorwrench said:
The Zenith types were the OEM carburetor. They are made from cast iron and are relatively easy to ID.

The Tillotson model X or XF carburettor is an aftermarket unit that is very near the same function but is shaped a bit differently and is made from zinc die cast. There was also a round bowl Tillotson for the model A but they aren't as common as the model X.

Marvel Schebler also manufactured a carburetor for the Ford model A. It is also a zinc die casting and was sold under various rebrands like the Johnson JFA and Allstate 2405. These carbs work well but are a bit less common than the Tillotson carbs.

You will need to ID the carb to get gaskets or other parts but parts are available for all of them as far as I know. There is also rebuild information for all of them. You won't find an automobile carburetor that is much easier to rebuild than these.
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Thank you very much.
 
The jets I bought from Bratton's were spot on. Katy

I didn't know that. Will order a set from Brattons and try them. Thanks, Katy!

Cavalier: Didn't know you were a mechanic. Sure, go through your carburetor yourself, like Rotorwrench says, Zeniths are not difficult to work on.
 
your carb should not drip.
lots of little annoyances when it comes to fixing your carburetor. but if you are mechanically inclined and if you want to know what to do next time it leaks, fix it yourself, ignore the suggestion to send it to a professional. you will learn nothing by sending your carburetor away.
you will end up having that carb on and off a dozen times but you will eventually know how it works and how to fix it.

float valve, float, main jet, cap jet, as well as the little gaskets around them and if there is any imperfections in the castings, these are items that will let gas drip out of the carb.
once you have the gas level at the correct height inside the float bowl of the carb, and have determined that the float valve is stopping gas flow when the gas is at that height the next check is to see if gas is coming out of the top of either the main jet or the cap jet. if so then those jets are too low. you can ad another fiber washer under the one thats leaking or you can buy a new jet that is the correct height.

there is a nice little book that is devoted to the model A ford carburetor. that is the first thing you should do, buy it
 
here is the book. hopefully it is still in print.
 

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As Bill Williamson said many years ago. They all leak, that’s why there is a shut off.

Gravity feed! May not leak today, but just give it a chance. In the summer you might not notice the moisture because of evaporation. In colder weather, you could start seeing moisture around the joints or in the throat. Also a drip or two on the engine pan.

Now if it’s flowing out or leaving a puddle? You do have a problem.

If the car is running good. Carb might just need to be taken apart and cleaned, with new gaskets added.

I would still recommend shutting off the gas valve when car is not being driven for any length of time.

Enjoy.
 
WHN said:
As Bill Williamson said many years ago. They all leak, that’s why there is a shut off.

Gravity feed! May not leak today, but just give it a chance. In the summer you might not notice the moisture because of evaporation. In colder weather, you could start seeing moisture around the joints or in the throat. Also a drip or two on the engine pan.

Now if it’s flowing out or leaving a puddle? You do have a problem.

If the car is running good. Carb might just need to be taken apart and cleaned, with new gaskets added.

I would still recommend shutting off the gas valve when car is not being driven for any length of time.

Enjoy.
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Assuming the valve doesn't leak too. Do one, do both. IMO, unless your car is a show car, replace the valve with a modern 1/4" ball valve. They NEVER leak.
 
Thank you all for the great info and the warm welcome also.
I will keep you posted on what I find. I can only work on this in my spare time so it takes a while.
Cheers
 
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cavalierhome said:
Ok I will start there, but ultimately I want to learn how to do my own work. I have never worked on a model A, but I did work on my race cars for many years and am pretty good around engines etc.

This is just a new adventure, I decided to start a little car collection, so far I have a 29 Model A, a 1986 Suzuki Samurai sitting in my garage.
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Same here Cav, I bought a carb outright from Bert's and then purchased the Paul Mollar and Steve Pargeter's restoration guides. I prefer Pargeter's book over the others. Tom Endy here on the forum has a great article on restoration. I then used the information to go through the carb that had been on the car.
 
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