Gas shut off still leaks

K

Kaptain Karl

Member
First I would like to thank everyones help on working on my ford, Now, I have another problem. I turn the car off and then shut the fuel off and the line does not leak, but today, I shut the fuel off and the carb was leaking fuel though the air cleaner for about 5 min. Is that just left over gravity feed through the line or do I have a bigger problem?
 
What I do, if you know the valve is good? I run the vehicle once parked till it stops by having no gas in the carb then turn the gas off.
 

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Have you installed an new aftermarket gas shutoff lately? If so this may be your problem in that it does not shut off completely. Or if not new, have you tightened your old one? Best way to check to see if they leak is to take your gas line loose and with the gas shut off, see if it still runs. If you have checked for a leak in your shutoff, then maybe your carb is filling up to much and the float needs adjustment. Just my guess and that is what they are in that I am no model A expert. Just a few things I have experienced.
 
It shouldn't be leaking if everything is right with the carb. The float level may be too high allowing overflow into the carb intake.
 
Float valve my be stuck open . Try tapping on the side of the carburator . Sometimes this will free up the valve .
 
Kaptain Karl said:
The valve has not leaked before, I think the float may be set too high. thanks for the help
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If it leaks then stops then that is your problem. You could just turn off the fuel and run it for a minute or two then shut down.

If the leak continues through out the day, then the problem is the shut off as well as the float. Lapping the fuel shut off works most of the time.
 
check the drain bolt at the bottom of the bowl, (the bolt which keeps the upper and lower housings together)?
 
If you suspect something is stuck in the carb needle and seat just turn the gas off and run it dry. Then when you turn the gas on, the inrush of fuel should wash it out.
 
After having doen everything listed above and if still having problems consider..Jets the right length? Fuel level set correct? leaking jet gaskets?
 
Sucked on a new quality repro valve, it leaked! Clamped it in the vise, squirted oil in it, worked it back & forth 117 times while pushing it in to "seat" & "settle" in the taper. NO MORE LEAK!! Yes, I know about toothpaste, it's for brushing teeth & polishing nickle plating. Bill W.
 
Yeah, toothpaste doesn't work. After buying a new Snyders "leakless" valve and also a recon kit for my old valve and trying a whole lot of other ideas all without any success, I was starting to tear my hair out. Finally in desperation I installed a brand new modern cut-off valve just downstream of the original valve and have had no problems since. The new valve is ugly and modern-looking but is tucked away under the dash and out of sight. I left the original valve in place.
 
Mike V. Florida said:
If the leak continues through out the day, then the problem is the shut off as well as the float. Lapping the fuel shut off works most of the time.
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I don't mean to hijack this, but I have had trouble with my valve leaking into the car. I took it apart and it was pretty scratched up, so I polished it with 800 grit paper. I got it to stop leaking but I had to tighten it up so much to keep from leaking, it is hard to turn.

I thought about lapping it, what would you use? Wouldn't regular valve lapping be too aggressive? I have some metal polishing rougue, I thought about trying.
 
whirnot said:
I don't mean to hijack this, but I have had trouble with my valve leaking into the car. I took it apart and it was pretty scratched up, so I polished it with 800 grit paper. I got it to stop leaking but I had to tighten it up so much to keep from leaking, it is hard to turn.

I thought about lapping it, what would you use? Wouldn't regular valve lapping be too aggressive? I have some metal polishing rougue, I thought about trying.
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White toothpase worked for me 8 years ago and still ok now.
 
Karl,
I am a seasoned restorer, and work on many "A" Fords.. although I don't consider myself an expert on all the carbs..... here is some of my experience learned through the years from my mentor Terry Oberer.

That's a strange syptom as either your fuel valve is leaking or you have an external leak or loose main or cap jet.... ( would let fuel leak through jet threads at carb bottom). If you want to isolate if your fuel valve is leaking or the carb needle and seat.. pull the carb off, use a makeshift fuel line and put the carb in the vise with the fuel line high for gravity fuel feed. With a small funnel and fuel tight connection, fill the carb ... Ensure that it is sitting in the vise at the same level as would be in the car. If your needle and seat is leaking, you will see the fuel level slowly lower in the funnel. if the plug on the bottom is leaking you will detect that.. if you can put a finger in the throat and feel fuel your float level is too high ( could be loose jet as well) as the fuel is topping over the level of the jets. Fuel float level 5/8"

It's best to check the needle and seat out of the carb with a vacuum gauge. if it will hold vacuum... it will not leak. IF it won't hold vacuum, it will leak. If it's a viton tip (black needle tip) all you can do is replace it. If it is a steel tip you can try to seat it better. My friend Terry Oberer taught me to give it a light "stake" or tap the needle lightly. It would better seat the two... I have used this a hundred times over and it does work. Keep using the vacuum gauge to ensure proper seating..

I've tried the vacuum test on new needle and seats both viton and steel... and have had very poor results out of the package new. I think it's a real problem out there right now. Why can't we get good seating needle and seats!!!! Walt Bratton we need your help on this! (he's good at getting things right)

On the the fuel line/valve.. if there is fuel leaking at all out of your line with the carb off... your valve is leaking just replace it with one of the new quality repros from a quality supplier. The new repros seem to be very good.. as opposed to how they use to be very poor. If you're restoring a point - show car of course you would want an original correct valve and know how to take the steps to make it optimum. AGain, use your vacuum pump to test.

I know that's a lot... but then it's all in the detail and being attentative as to what's going on. Tom Endy has a good article on the web about restoring carbs...They are simple and then not!

Oh.. one last tip... if you ever remove the main and cap jets... make sure you get all of the gasket"(s) as typically with the main there can be more than one (previously not removed) from the carb base. This in itself changes the jet height.

Good luck,
Larry Shepard
 
Larry, why do you need an original needle & seat on a high points show car. Buster asks, "Do them Judges, (Bless their hearts!) have X-Ray Vision"?? Bill W.
 
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