Fuel leaking through carb when parked

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Model T Ford Forum: Forum 2013: Fuel leaking through carb when parked
Top of pagePrevious messageNext messageBottom of page Link to this message  By William Rowles on Friday, November 15, 2013 - 04:52 am:

When I started driving my 1920 Runabout I noticed the carb dripped fuel from the air intake onto the drip pan in the garage. I tried to close the shutoff valve at the tank but it is stuck in open position. I bought and installed the shutoff valve sold by the parts vendors that replaces the elbow at the carb. After a couple years of use, the new shutoff valve leaks-through and the carb drips again while parked. I drained the tank before winter storage today, but need to plan some corrective action for next Spring before fueling the tank again. I would appreciate some advice from the experienced sages here on this topic; what to fix and how to correct the carb-dripping that wastes fuel, is dangerous and stinky in the garage.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Friday, November 15, 2013 - 07:24 am:

Larry Smith manufactures a good quality original style needle and seat assembly. It is sold through Langs and Chaffins, among others. I would start by replacing that, then be sure the float level is appropriate.

Second, get a modern ball valve shutoff. These have Teflon and stainless steel guts, able to resist today's water sodden and chemical laced fuel with good long term service.

Modern valve seen here was $7.49 at the local True Value hardware store:


Top of pagePrevious messageNext messageBottom of page Link to this message  By James Chochole on Friday, November 15, 2013 - 09:32 am:

Agreed- a good solid modern or new-made shut-off will solve your fuel issue.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Friday, November 15, 2013 - 09:42 am:

If you have a Holley NH, your float setting from the flange to the flat side of the float may be too small. If the gap is less than 15/64" the float will not stop the flow of gas into the bowl before closing the needle valve resulting in an overflow of gas. If the gap is too great, the float will close the valve before the gas in the bowl has reached the proper level, resulting in a perpetual starvation of fuel. Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Grady L Puryear on Friday, November 15, 2013 - 10:15 am:

Having grown up with this type of arrangement, I still like it and use it, it is a combination glass bowl filter and shut off. These were commonly used on tractors and etc. back in the day. I use one coming out of the fuel tank, and one right before the carburetor. I get mine at Farm stores, Tractor Supply, John Deere, etc., you have to sometimes get one or two if you happen to get one made in China, but in the main, they are usually good. There is an amazing amount of water that is caught by these systems.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Friday, November 15, 2013 - 11:09 am:

While the fuel is out, you need to fix the valve at the fuel bulb under the gas tank. That one should always work because of the following:

I have not yet found a modern valve which mounts at the elbow or near it to last more than a year. At first they work perfectly, then they get so tight I need pliars to turn and eventually they will leak.

The float valve in the carburetor must be good. A good test is to leave the fuel valve on and put a can under the carburetor. Park for a few hours and check the can to see if it has gas in it. Normally turn off the gas when you park. The above is only to test the float valve.

On a carburetor I recently worked on, I had fuel coming out the air intake. I took off the bowl and found the float all the way up against the body of the carburetor. I adjusted the float level and put the carburetor back on. The leak was worse. Then I took it off again and found metal fatigue in the brass tab on the float. Every time I would bend it to the correct float level setting it would bend back and the float would raise. Lucky, I found another float with a good tab, but it leaked worse than before. This time I found that the tab was not square with the needle and would stick holding the needle open. Finally some bending and I got it right.

Anyway, It is good to have the valve at the tank in good working condition even if you use another valve near the carburetor. You never know when something will leak.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Friday, November 15, 2013 - 12:49 pm:

You can also test the sealing ability of the NH carburetor's needle valve by removing the carburetor turning it upside down and sucking on the fuel intake el. Be sure to first drain all the gas out of it and let it dry real good before performing this test. If you have a good seal you will be able to create a vacuum that will cause your tongue to stick to the opening of the el. If you do not have a good seal, you will be able to suck air through the leaks around the needle valve and its' seat. Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Anthonie Boer on Friday, November 15, 2013 - 03:03 pm:

William , Is this where you are looking for ?
1099R
1100R
1102R
Toon.


Top of pagePrevious messageNext messageBottom of page Link to this message  By William Rowles on Saturday, November 16, 2013 - 11:35 pm:

Thank you all for the helpful advise. I can now plan a course of action and purchase some parts to be ready to solve my problem when the car comes out of storage next Spring.


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