The Ford Barn

Msaby · 07-18-2013, 08:45 PM

My carburetor developed a leak. It is a tillotson carb. The leak appears to be between the 2 halves, is this typical with these carburetors warping?

I finally get this car running so darn good and now this. Any suggestion?

Thanks

Mike

Ed in Maine · 07-18-2013, 09:19 PM

Hello Mike, I think you have the level too high in the bowl and this is why the carb is leaking out of the vent. Readjust the float level to lower the gasoline level in the bowl. I don't remember the distance measurement. Alternatively, you have a particle of dirt on the float level valve seat and the float valve is not shutting off tightly. This is easily cleaned by disassembling the carb and flushing the valve seat. Ed

Msaby · 07-18-2013, 10:29 PM

I have checked and tested the needle/seat and it appears to be okay. I set the float per manufacture spec at 1" from the gasket surface. It appears to be leaking on the side closest to the engine block.

1931 flamingo · 07-19-2013, 04:20 PM

Pull it apart and ck for warpage of either the top or bottom or both.
Paul in CT

Robert Putnam · 07-19-2013, 05:27 PM

They are very prone to warping. I built a jig to clamp the upper body to. It has a serious of small clamps the surround the perimeter of the upper half. I put the jig and carb into my wife's oven and heat it up to about 450, then start tightening the clamps. Works pretty darn well. The jig is just a piece of half inch plate about 6inches square machined flat. Not difficult to make if you have access to a miller or a good friend with one.

H. L. Chauvin · 07-19-2013, 05:54 PM

Sponsored Links (Register now to hide all advertisements)

Robert is correct.

1. When one tightens the screws, the soft gasket between the pot metal halves compress more at screw locations.

2. The metal immediately adjacent to and surrounding the screws becomes distorted & the metal on the top half & bottom half moves inwards towards the gasket.

3. If one places both halves on a sheet of glass or a very flat surface, one can verify a very small gap between the pot metal & the flat surface.

4. In some cases, the halves can be very carefully filed "flat" at the screw locations using a large flat file to remove a few thousandths of an inch at the "raised" areas.

Also the latest small "black" carburetor jet gaskets offered by some vendors were introduced to replace the small "red" jet gaskets which were prone to leak profusely after getting soaked with fuel.

Hope this helps.

rfincher · 02-25-2014, 11:52 AM

I have a similar problem in that there is a major leak at the air vent. When I take the carb apart - no apparent warp, good gasket. I can stop the flow of gas with the float valve with pressure from my finger. Float appears to be at correct 5/8" height.

Can't see the innerworkings of the float valve. Are the float valves originally equipped with a rubber tip to easily seal? My float valve "sounds" all metal.

Tom Wesenberg · 02-25-2014, 04:53 PM

Quote:

Originally Posted by rfincher

I have a similar problem in that there is a major leak at the air vent. When I take the carb apart - no apparent warp, good gasket. I can stop the flow of gas with the float valve with pressure from my finger. Float appears to be at correct 5/8" height.

Can't see the innerworkings of the float valve. Are the float valves originally equipped with a rubber tip to easily seal? My float valve "sounds" all metal.

Original tips are steel and after I lapped mine with toothpaste it seals perfectly for over 10 years.

Does your float have gas in it?

cfordman · 02-25-2014, 05:26 PM

I had an experience with a tillotson carb on a 1928 Durant several yrs ago. It appeared the carb was flooding, it leaked gas at the gasket between the top and bowl. I tried everything that was suggested here, it did not seem to leak when running but became wet after sitting. here's what I found. if I mounted the dry bowl in a vice with the top off and poured a 1/2 inch of gas into the bowl with in a matter of 30 secs the top lip (sealing surface) became wet. the gas was actually seeping into the porous metal of the carb and wicking its way up to the top. there was some talk about a sealer that was applied to the carb when it was new and this disappers over time. I think there was an ad in hemmings for a cure. maybe someone can add to the story. I never got it to quit, bought a new carb.

07-18-2013, 08:45 PM	#1
Msaby Member Join Date: May 2013 Location: Allentown, Pa. Posts: 37	Fuel Leak My carburetor developed a leak. It is a tillotson carb. The leak appears to be between the 2 halves, is this typical with these carburetors warping? I finally get this car running so darn good and now this. Any suggestion? Thanks Mike

07-18-2013, 09:19 PM	#2
Ed in Maine Senior Member Join Date: May 2010 Location: Washington Cty., ME or Flagler Cty., FL Posts: 1,106	Re: Fuel Leak Hello Mike, I think you have the level too high in the bowl and this is why the carb is leaking out of the vent. Readjust the float level to lower the gasoline level in the bowl. I don't remember the distance measurement. Alternatively, you have a particle of dirt on the float level valve seat and the float valve is not shutting off tightly. This is easily cleaned by disassembling the carb and flushing the valve seat. Ed

07-18-2013, 10:29 PM	#3
Msaby Member Join Date: May 2013 Location: Allentown, Pa. Posts: 37	Re: Fuel Leak I have checked and tested the needle/seat and it appears to be okay. I set the float per manufacture spec at 1" from the gasket surface. It appears to be leaking on the side closest to the engine block.

07-19-2013, 04:20 PM	#4
1931 flamingo Senior Member Join Date: May 2010 Location: new britain,ct 06052 Posts: 9,390	Re: Fuel Leak Pull it apart and ck for warpage of either the top or bottom or both. Paul in CT

07-19-2013, 05:27 PM	#5
Robert Putnam Member Join Date: May 2010 Posts: 41	Re: Fuel Leak They are very prone to warping. I built a jig to clamp the upper body to. It has a serious of small clamps the surround the perimeter of the upper half. I put the jig and carb into my wife's oven and heat it up to about 450, then start tightening the clamps. Works pretty darn well. The jig is just a piece of half inch plate about 6inches square machined flat. Not difficult to make if you have access to a miller or a good friend with one.

07-19-2013, 05:54 PM	#6
H. L. Chauvin Senior Member Join Date: May 2010 Posts: 4,179	Re: Fuel Leak Sponsored Links (Register now to hide all advertisements) Robert is correct. 1. When one tightens the screws, the soft gasket between the pot metal halves compress more at screw locations. 2. The metal immediately adjacent to and surrounding the screws becomes distorted & the metal on the top half & bottom half moves inwards towards the gasket. 3. If one places both halves on a sheet of glass or a very flat surface, one can verify a very small gap between the pot metal & the flat surface. 4. In some cases, the halves can be very carefully filed "flat" at the screw locations using a large flat file to remove a few thousandths of an inch at the "raised" areas. Also the latest small "black" carburetor jet gaskets offered by some vendors were introduced to replace the small "red" jet gaskets which were prone to leak profusely after getting soaked with fuel. Hope this helps.

02-25-2014, 11:52 AM	#7
rfincher Junior Member Join Date: Feb 2014 Posts: 3	Re: Fuel Leak I have a similar problem in that there is a major leak at the air vent. When I take the carb apart - no apparent warp, good gasket. I can stop the flow of gas with the float valve with pressure from my finger. Float appears to be at correct 5/8" height. Can't see the innerworkings of the float valve. Are the float valves originally equipped with a rubber tip to easily seal? My float valve "sounds" all metal.

02-25-2014, 05:26 PM	#9
cfordman Member Join Date: Jan 2014 Posts: 66	Re: Fuel Leak I had an experience with a tillotson carb on a 1928 Durant several yrs ago. It appeared the carb was flooding, it leaked gas at the gasket between the top and bowl. I tried everything that was suggested here, it did not seem to leak when running but became wet after sitting. here's what I found. if I mounted the dry bowl in a vice with the top off and poured a 1/2 inch of gas into the bowl with in a matter of 30 secs the top lip (sealing surface) became wet. the gas was actually seeping into the porous metal of the carb and wicking its way up to the top. there was some talk about a sealer that was applied to the carb when it was new and this disappers over time. I think there was an ad in hemmings for a cure. maybe someone can add to the story. I never got it to quit, bought a new carb.