The Ford Barn

coody · 06-23-2025, 08:57 PM

i have a 31 AA truck in the shop with a small fuel leak. It is coming from the
adjusting needle housing. I removed the needle and waited awhile and it will seep up and run out of the needle housing.it takes about a half day to come to the top. Even with the gas off it seep out. It has a new gas shut off valve & the carb been rebuilt. This just started. The carb was rebuilt about a year ago. Any suggestions? tks!!

nkaminar · 06-24-2025, 05:05 AM

In order for it to be leaking there could be 3 things wrong. A combination of the shutoff valve and the float valve leaking could cause this and the GAV housing leaking.

Take the fuel line off the carburetor and place it over a container and wait a while to see if gasoline is coming from your shut off valve. Even a new one will sometimes leak.

The other two things will require taking the carburetor apart. Check to see that the float valve is not leaking, adjusted correctly, and that the gasket is not leaking. Unscrew the GAV housing to see if it is sealing correctly. The threads are a pipe thread so you may want to try a little Teflon tape to seal it.

A good site for the Zenith carburetor is https://modela.org/default.html

coody · 06-24-2025, 06:34 AM

I will take the fuel line off and check.If it is leaking can a new one be repaired w/o buying another one? I will check the site on the carbs too! tks for your help on this!!

nkaminar · 06-24-2025, 07:05 AM

If the fuel valve is leaking you can use EZ Turn to fix it, see link below. One tube will last a lifetime. It is a grease that is not effected by gasoline. You will have to drain your tank and take the valve apart. If you use your shutoff valve a lot you will have to add more in about 6 months. Some Barner has advised that, after you drain the tank, jack up the starboard side 4 to 6 inches to move any remaining gasoline to the port side.

https://www.aircraftspruce.com/catal...s/09-00306.php

katy · 06-24-2025, 09:34 AM

Quote:

Originally Posted by nkaminar

If the fuel valve is leaking you can use EZ Turn to fix it, see link below. One tube will last a lifetime. It is a grease that is not effected by gasoline.

What colour is it?

nkaminar · 06-24-2025, 09:41 AM

Sponsored Links (Register now to hide all advertisements)

I cannot remember exactly but a clear or very light translucent white. Maybe like Vasoline.

katy · 06-24-2025, 09:45 AM

Thanks

Y-Blockhead · 06-24-2025, 10:42 AM

Yes like vasoline but thicker. Good stuff. I use it on my S/O valve and carb throttle shafts and other carb parts.

Y-Blockhead · 06-24-2025, 10:55 AM

If you end up having to replace the gas S/O valve, ensure you get the new design from Snyder's that has a ball valve. https://www.snydersantiqueauto.com/p...9339&cat=41707

Gene F · 06-24-2025, 12:30 PM

Quote:

Originally Posted by nkaminar

In order for it to be leaking there could be 3 things wrong. A combination of the shutoff valve and the float valve leaking could cause this and the GAV housing leaking.

Take the fuel line off the carburetor and place it over a container and wait a while to see if gasoline is coming from your shut off valve. Even a new one will sometimes leak.

The other two things will require taking the carburetor apart. Check to see that the float valve is not leaking, adjusted correctly, and that the gasket is not leaking. Unscrew the GAV housing to see if it is sealing correctly. The threads are a pipe thread so you may want to try a little Teflon tape to seal it.

A good site for the Zenith carburetor is https://modela.org/default.html

Isn't there supposed to be a little dimple in the very end of the primary jet?

Gary WA · 06-24-2025, 01:02 PM

Quote:

Originally Posted by coody

i have a 31 AA truck in the shop with a small fuel leak. It is coming from the
adjusting needle housing. I removed the needle and waited awhile and it will seep up and run out of the needle housing.it takes about a half day to come to the top. Even with the gas off it seep out. It has a new gas shut off valve & the carb been rebuilt. This just started. The carb was rebuilt about a year ago. Any suggestions? tks!!

Main Jet may not be the popper length?! and not dished? or jets may be loose?

nkaminar · 06-24-2025, 02:55 PM

https://modela.org/default.html

06-23-2025, 08:57 PM	#1
coody Junior Member Join Date: Jun 2025 Posts: 2	carburetor leaking issues i have a 31 AA truck in the shop with a small fuel leak. It is coming from the adjusting needle housing. I removed the needle and waited awhile and it will seep up and run out of the needle housing.it takes about a half day to come to the top. Even with the gas off it seep out. It has a new gas shut off valve & the carb been rebuilt. This just started. The carb was rebuilt about a year ago. Any suggestions? tks!!

06-24-2025, 05:05 AM	#2
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,871	Re: carburetor leaking issues In order for it to be leaking there could be 3 things wrong. A combination of the shutoff valve and the float valve leaking could cause this and the GAV housing leaking. Take the fuel line off the carburetor and place it over a container and wait a while to see if gasoline is coming from your shut off valve. Even a new one will sometimes leak. The other two things will require taking the carburetor apart. Check to see that the float valve is not leaking, adjusted correctly, and that the gasket is not leaking. Unscrew the GAV housing to see if it is sealing correctly. The threads are a pipe thread so you may want to try a little Teflon tape to seal it. A good site for the Zenith carburetor is https://modela.org/default.html __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 06-24-2025 at 05:14 AM.

06-24-2025, 06:34 AM	#3
coody Junior Member Join Date: Jun 2025 Posts: 2	Re: carburetor leaking issues I will take the fuel line off and check.If it is leaking can a new one be repaired w/o buying another one? I will check the site on the carbs too! tks for your help on this!!

06-24-2025, 07:05 AM	#4
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,871	Re: carburetor leaking issues If the fuel valve is leaking you can use EZ Turn to fix it, see link below. One tube will last a lifetime. It is a grease that is not effected by gasoline. You will have to drain your tank and take the valve apart. If you use your shutoff valve a lot you will have to add more in about 6 months. Some Barner has advised that, after you drain the tank, jack up the starboard side 4 to 6 inches to move any remaining gasoline to the port side. https://www.aircraftspruce.com/catal...s/09-00306.php __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

06-24-2025, 09:41 AM	#6
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,871	Re: carburetor leaking issues Sponsored Links (Register now to hide all advertisements) I cannot remember exactly but a clear or very light translucent white. Maybe like Vasoline. __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.

06-24-2025, 09:45 AM	#7
katy Senior Member Join Date: Jun 2015 Location: Red Deer, Alberta Posts: 5,716	Re: carburetor leaking issues Thanks __________________ If you don't hear a rumor by 10 AM, start one!. Got my education out behind the barn!

06-24-2025, 10:42 AM	#8
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 6,651	Re: carburetor leaking issues Yes like vasoline but thicker. Good stuff. I use it on my S/O valve and carb throttle shafts and other carb parts.

06-24-2025, 10:55 AM	#9
Y-Blockhead Senior Member Join Date: Jul 2011 Location: Redondo Beach, CA Posts: 6,651	Re: carburetor leaking issues If you end up having to replace the gas S/O valve, ensure you get the new design from Snyder's that has a ball valve. https://www.snydersantiqueauto.com/p...9339&cat=41707

06-24-2025, 02:55 PM	#12
nkaminar Senior Member Join Date: Jan 2012 Location: Western North Carolina Posts: 5,871	Re: carburetor leaking issues https://modela.org/default.html __________________ A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past.