carburetor leaking issues

C

coody

New member
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!!
 
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
 
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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!!
 
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/catalog/pnpages/09-00306.php
 
Yes like vasoline but thicker. Good stuff. I use it on my S/O valve and carb throttle shafts and other carb parts.
 
nkaminar said:
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
Click to expand...

Isn't there supposed to be a little dimple in the very end of the primary jet?
 
coody said:
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!!
Click to expand...
Main Jet may not be the popper length?! and not dished? or jets may be loose?
 

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