Shut-off valve/carburetor question

TPR1930

TPR1930

Junior Member
I’ve replaced my shut-off valve successfully and a now have no leaks and terrific flow to my carburetor. Prior to this, my car was running very well. Now after hooking everything back up, I’m having trouble getting started. After repeated tries of almost catching, it will run for a few seconds before stalling. Once it ran well for about two minutes, before failing. I was very careful during the whole process to make sure I was sediment free. My screens are all clean, shut-off, sediment bowl and carburetor. Gas is brand new ethanol-free. At shut-down, I’ve been using the shut-off and allowing the line to drain. It was sitting for a few weeks since last run. Does anyone think this could have been enough for the float to freeze in position? I tried hitting on the side with a wrench to free it ~ No help there. If it is this, does it mean a carb rebuild? Is there an easier fix? All thoughts, as always, are appreciated.
 
Make sure you didn't put the fuel line to carb in to far hitting the screen slowing the flow. If you have a zenith carb.
 
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Thank you for the advice. I readjusted the fuel line, and after a few tries got it started. It ran well for about 5 minutes, at idle, and then stopped. At that moment, it did sound like the gas was being shut off. I think my next step might be taking the carb off and giving it a visual exam. I'm waiting for a rebuilt carb to come in a few weeks. If no one has anymore thoughts, that in the end might solve my problem. Again, thank you.
 
Somewhat as an aside, I have found that if I run the bowl dry after shutting off, when I open it up again to start the carb has a tendency to flow fuel out the air inlet, almost as if the float valve is stuck open. So I turn off the gas at the petcock, idle it for about 5 seconds to get the fuel level down but not completely depleted, then shut off the engine. Seems to have cured the problem.

JayJay
 
Remove the one bolt at the bottom of the carb and the lower half of the carburetor will come off as long as the venturi isn't stuck.
Squirt some carb cleaner into the jets etc... in the lower half and blow it out.
Your float will be exposed and hanging free so you can raise and lower it a few times to limber it up before you put the bottom back on.
 
It does sound like a fuel problems but check the ignition anyway. To check for fuel flow, remove the small bolt at the bottom of the carburetor and observe the flow into a bucket. Do this outside with a fire extinguisher handy. This tests the whole system, from tank to the bottom of the carburetor.

The Zenith carburetor is easy to work on. Do not be intimidated by it. If needed, take it off and split it apart. Use some spray carburetor cleaner and blow out all the jets and passages and the float valve. You probably do not have to take any parts out but if you do keep track of them so you don't loose them.

A good site for the Zenith carburetor is https://model-a.org/default.html
 
Regarding the shutoff petcock. The parts are brass on brass and will eventually gall. Add the EZ Turn petcock lube before that happens, see link below. A 5 ounce tube will last your lifetime. You can use the lube on any other parts that move in gasoline or need to be sealed. Once the petcock parts gall they do not completely seal.

1. Drain the tank when it gets to the 0 mark. Do this outside with plenty of ventilation and have a fire extinguisher handy.

2. Remove the handle. Do not loose the nut or lock washer.

3. Remove the nut that retains the turning part. Take note of the order of the washers and spring and do not loose the parts.

4. Pull out the turning part. You may have to re-install the handle to pull it out. You can use a small open end wrench to carefully pry. Note how the turning part is oriented in the petcock.

5. Smear the EZ Turn on the turning part. A moderate amount works best but not so much that it blocks the holes.

6. Replace the turning part in the same orientation that it was taken out.

7. Assemble the rest of the parts in reverse order of the disassembly.

8. Test the petcock to make sure it is operating correctly and check for leaks. Admire how well it moves.

https://www.aircraftspruce.com/catalog/cspages/ezturnlube.php
 
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As my update .. My restored carburetor has returned from Mike’s looking like a gem. It has been installed, and the car is running like a champ. Started up on second try. I can only think that my initial problem may have been a case of when it rains, it pours. Prior to not being able to start, my GAV was not working as usual. Sort of floating around, then at times not working at all. Whatever the reason, it is now gone. Thank you everyone for your thoughts on solutions.
 
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