The Ford Barn

Brobrian · 10-26-2014, 11:05 PM

Check my thinking here.
I got a Zenith carb from Snyders. But it leaks gas out the air intake. I took it apart, cleaned it out. The float appeared to be set properly, though I didn't set up the little test with the clear fuel line. Instead, to check I took the float valve out and doubled up the washer before I reinstalled it. When raised fully the float was clearly lower that it had been before by quite a bit. That should have made the float shut off the valve at a lower level in the bowl. However, the carb still leaked prodigiously as before. I concluded that the float valve on my new carb was not shutting off the fuel as it should. So now I guess I'll get another valve for it.

Sound reasonable?

By the way, I had another carb and put it on, no leaks, works great.

johnbuckley · 10-27-2014, 03:20 AM

Here's a hit list for Zeniths:Causes of leaking
Problem: Remedy
1 Leaking/loose float valve gasket: Tighten/reseal/replace
2 Leaking float valve: Replace
3 Friction on float hinge: Loosen
4 Incorrectly set fuel level: Re-set
5 Hole in float: Repair or replace
6 Cap jet or Main jet too short/ more than one gaskets on main jet: check
7 Leaking/loose gasket at main jet: Tighten/reseal/ replace
8 Leaking /loose gasket at cap jet: Tighten/replace
9 Leaking or loose GAV housing threads: Tighten/ reseal/ replace
10 Leak at fuel inlet union: Tighten/reseal/replace
11 Loose/leaking gasket at strainer: Tighten/reseal/replace
12 Loose/leaking gasket at drain plug: Tighten/reseal/replace
13 Cracked housing/leaking passage plugs: Repair or replace

jmeckel · 10-27-2014, 07:35 AM

Modern float valves can have issues, take it apart carefully and lap with toothpaste, clean it up and reassemble. All most always solves the problem.

johnbuckley · 10-27-2014, 08:10 AM

Quote:

Originally Posted by jmeckel

Modern float valves can have issues, take it apart carefully and lap with toothpaste, clean it up and reassemble. All most always solves the problem.

I'm sure it does, but what a sad reflection on modern parts that one may need to go through this procedure- and I reckon that for most people ( me included!) attempting dis-assembly and re- assembly of a float valve is going to create more co-lateral damage to it than it cures. ( I check every new part that I get for carbs - jets, floats, valves, gaskets even -the lot; have come across manufacturing faults on each and every one at one time or another.)

JOES31 · 10-27-2014, 08:28 AM

I had this same problem a while ago. I purchased 2 rebuilt carbs from a reputable source. First one leaked. The second one leaked less but the car ran terrible. I sent those back and bought the rebuild kit from Snyder's and flow tested jets from Renner's and rebuilt the thing myself. It ran pretty good without any leaks.

Later I stumbled across a new style Zenith model # 13922. It is a brand blew carb that runs really well on the A. No more leaks, backfires and runs smooth. Quite a few guys here on the barn have installed them and love them.

ModAfan · 10-27-2014, 01:41 PM

Sponsored Links (Register now to hide all advertisements)

When I had the same problem it turned out that the gas shutoff valve under the gas tank was leaking. The valve was 86-years-old, so I didn't hold a grudge against it.
It was probably the case that the weight of the fuel in the gas tank, which is quite a bit higher than the carburetor, overpowered the ability of any float valve to stop the flow of gas. Gravity can be cruel. As soon as I replaced the gas shutoff valve all was well.

Mitch//pa · 10-27-2014, 02:23 PM

Quote:

Originally Posted by ModAfan

When I had the same problem it turned out that the gas shutoff valve under the gas tank was leaking. The valve was 86-years-old, so I didn't hold a grudge against it.
It was probably the case that the weight of the fuel in the gas tank, which is quite a bit higher than the carburetor, overpowered the ability of any float valve to stop the flow of gas. Gravity can be cruel. As soon as I replaced the gas shutoff valve all was well.

yep i agree with this statement... i usually service both valves at the same time for leakage problems

fiddlybits · 10-27-2014, 03:27 PM

It may not be the valve... it may be the the threads that are leaking.
I had this same problem and it would leak even when I changed valves. Finally figured it out and wrapped a little teflon thread in the threads... voila... no more leak.

rocket1 · 10-27-2014, 03:47 PM

If you have only got that Snyders carb a short time,send it BACK!

10-26-2014, 11:05 PM	#1
Brobrian Senior Member Join Date: Jan 2012 Location: Riverside, CA Posts: 315	Is the Carb leaking due to Float Valve? Check my thinking here. I got a Zenith carb from Snyders. But it leaks gas out the air intake. I took it apart, cleaned it out. The float appeared to be set properly, though I didn't set up the little test with the clear fuel line. Instead, to check I took the float valve out and doubled up the washer before I reinstalled it. When raised fully the float was clearly lower that it had been before by quite a bit. That should have made the float shut off the valve at a lower level in the bowl. However, the carb still leaked prodigiously as before. I concluded that the float valve on my new carb was not shutting off the fuel as it should. So now I guess I'll get another valve for it. Sound reasonable? By the way, I had another carb and put it on, no leaks, works great. __________________ Forty horses is plenty.

10-27-2014, 03:20 AM	#2
johnbuckley Senior Member Join Date: Jul 2010 Location: United Kingdom Posts: 1,556	Re: Is the Carb leaking due to Float Valve? Here's a hit list for Zeniths:Causes of leaking Problem: Remedy 1 Leaking/loose float valve gasket: Tighten/reseal/replace 2 Leaking float valve: Replace 3 Friction on float hinge: Loosen 4 Incorrectly set fuel level: Re-set 5 Hole in float: Repair or replace 6 Cap jet or Main jet too short/ more than one gaskets on main jet: check 7 Leaking/loose gasket at main jet: Tighten/reseal/ replace 8 Leaking /loose gasket at cap jet: Tighten/replace 9 Leaking or loose GAV housing threads: Tighten/ reseal/ replace 10 Leak at fuel inlet union: Tighten/reseal/replace 11 Loose/leaking gasket at strainer: Tighten/reseal/replace 12 Loose/leaking gasket at drain plug: Tighten/reseal/replace 13 Cracked housing/leaking passage plugs: Repair or replace

10-27-2014, 07:35 AM	#3
jmeckel Senior Member Join Date: Sep 2011 Location: Luck WI Posts: 550	Re: Is the Carb leaking due to Float Valve? Modern float valves can have issues, take it apart carefully and lap with toothpaste, clean it up and reassemble. All most always solves the problem. __________________ Jon "If you choose to not decide, you still have made a choice!" RUSH Don't tell me what you know..... Tell me what you have done.

10-27-2014, 08:28 AM	#5
JOES31 Senior Member Join Date: Apr 2014 Location: La Verne California Posts: 283	Re: Is the Carb leaking due to Float Valve? I had this same problem a while ago. I purchased 2 rebuilt carbs from a reputable source. First one leaked. The second one leaked less but the car ran terrible. I sent those back and bought the rebuild kit from Snyder's and flow tested jets from Renner's and rebuilt the thing myself. It ran pretty good without any leaks. Later I stumbled across a new style Zenith model # 13922. It is a brand blew carb that runs really well on the A. No more leaks, backfires and runs smooth. Quite a few guys here on the barn have installed them and love them.

10-27-2014, 01:41 PM	#6
ModAfan Senior Member Join Date: Jul 2014 Location: Near Boston Posts: 135	Re: Is the Carb leaking due to Float Valve? Sponsored Links (Register now to hide all advertisements) When I had the same problem it turned out that the gas shutoff valve under the gas tank was leaking. The valve was 86-years-old, so I didn't hold a grudge against it. It was probably the case that the weight of the fuel in the gas tank, which is quite a bit higher than the carburetor, overpowered the ability of any float valve to stop the flow of gas. Gravity can be cruel. As soon as I replaced the gas shutoff valve all was well.

10-27-2014, 03:27 PM	#8
fiddlybits Senior Member Join Date: Jan 2014 Location: N Illinois Posts: 447	Re: Is the Carb leaking due to Float Valve? It may not be the valve... it may be the the threads that are leaking. I had this same problem and it would leak even when I changed valves. Finally figured it out and wrapped a little teflon thread in the threads... voila... no more leak.

10-27-2014, 03:47 PM	#9
rocket1 Senior Member Join Date: Mar 2014 Location: Midland Park,N.J. Posts: 1,108	Re: Is the Carb leaking due to Float Valve? If you have only got that Snyders carb a short time,send it BACK!