Bad carb float again?

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Bad carb float again?

Post by ivaldes1 » Sat Mar 13, 2021 11:45 pm

Hi all, Back again after the Texas armageddon freeze. I've spent the last few weeks recovering and finally getting down to rewiring the house for solar critical load panel and a generator for hurricane season.

A few years ago I had a bad carburetor float. Gas pouring out of the Holley NH. I bought a new float and it fixed the problem. The car had been running fine for months, until this past week. Nothing done to the carburetor. It is baaack! Gas pouring out of the carb throat and it will not start until I turn off the sediment bulb gas. I checked and reset the float angle to 1/4 inch gap but it still is pouring gas out. Do carb floats go bad that fast? I didn't do the boiling water float test yet. Could it be anything else?

-- IV

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Re: Bad carb float again?

Post by Steve Jelf » Sun Mar 14, 2021 12:06 am

Yes, it could be a bad float valve. What do you have?
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Re: Bad carb float again?

Post by BobShirleyAtlantaTx » Sun Mar 14, 2021 1:25 am

Shake the float and generally if it has gas in it you will feel the gas and see a wet spot. You can also drop the float in very hot - but not boiling water, hold it submerged with a stick or something and check for air bubbles. If you see bubbles you got a problem.

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Re: Bad carb float again?

Post by ivaldes1 » Sun Mar 14, 2021 1:27 am

Holley NH. They can go bad after only a few years?
Steve Jelf wrote:
Sun Mar 14, 2021 12:06 am
Yes, it could be a bad float valve. What do you have?


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Re: Bad carb float again?

Post by jiminbartow » Sun Mar 14, 2021 1:29 am

Hollow brass or shellacked cork? When selling the float, be sure to measure from the flange to the top of the float. Jim Patrick

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Re: Bad carb float again?

Post by ivaldes1 » Sun Mar 14, 2021 1:59 am

Hollow brass purchased from a reputable vendor. I think I measured and re-set the float correctly per the diagram. It has been working fine for the last few years so I am at a loss as to why it suddenly has developed a problem.
jiminbartow wrote:
Sun Mar 14, 2021 1:29 am
Hollow brass or shellacked cork? When selling the float, be sure to measure from the flange to the top of the float. Jim Patrick


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Re: Bad carb float again?

Post by bobt » Sun Mar 14, 2021 7:07 am

What kind of float VALVE (NEEDLE AND SEAT) DO YOU HAVE?


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Re: Bad carb float again?

Post by Dan Hatch » Sun Mar 14, 2021 9:45 am

What gas mixture are you using in it. Pure gas or?


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Re: Bad carb float again?

Post by TXGOAT2 » Sun Mar 14, 2021 10:03 am

Dirt.... dirt in the fuel line... just blow it away....

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Re: Bad carb float again?

Post by Steve Jelf » Sun Mar 14, 2021 12:10 pm

Holley NH. They can go bad after only a few years?

No, I meant to ask Bob's question. What kind of valve? Some of them are prone to sticking and leaking. Some of them also come with a gasket that's too hard to seal, so gas leaks around the seat. Your flooding could be due to a sinking float, or a leaking valve, or both.
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Re: Bad carb float again?

Post by ivaldes1 » Sun Mar 14, 2021 2:29 pm

The float is tested in hot water there are no bubbles and I see no obvious holes or damage. Shaking it I hear no liquid inside. The needle is the Viton tip kind. This is a Russ Potter rebuild from 4 ish years ago.

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Re: Bad carb float again?

Post by ivaldes1 » Sun Mar 14, 2021 2:31 pm

I don't know. Usually Valero premium.
Dan Hatch wrote:
Sun Mar 14, 2021 9:45 am
What gas mixture are you using in it. Pure gas or?

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Re: Bad carb float again?

Post by RajoRacer » Sun Mar 14, 2021 2:43 pm

Ignacio - is the gas tank an original ? If so, perhaps there is residual crud getting to the float needle & seat.

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Re: Bad carb float again?

Post by George House » Sun Mar 14, 2021 3:35 pm

Our dearly departed friend Jack Daron told me how to test the functionality of an NH float :
Lay it down on a concrete floor and stomp on it. If liquid splattered out onto the floor, it wasn’t any good.
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Re: Bad carb float again?

Post by ivaldes1 » Sun Mar 14, 2021 3:45 pm

Not original, looks clean on the inside.
RajoRacer wrote:
Sun Mar 14, 2021 2:43 pm
Ignacio - is the gas tank an original ? If so, perhaps there is residual crud getting to the float needle & seat.

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Re: Bad carb float again?

Post by ivaldes1 » Sun Mar 14, 2021 3:52 pm

Seat looks clean, see picture. In thinking about this I did recently grease the sediment bulb petcock valve and the carburetor fuel line nut and elbow with fuel-proof grease to stop fuel from seeping. That coincided with this problem. However, I am failing to see how that would be a problem but I have no explanation for the current situation either. Could the grease have traveled and make the fuel valve stick open somehow? I could try a Q-tip on the valve bore.
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Re: Bad carb float again?

Post by DanTreace » Sun Mar 14, 2021 4:18 pm

Use some carb cleaner or lacquer thinner, avoid cotton swab due to cotton particles. As posted, a speck of trash, including a dab of gas resistance grease, can stick the needle.

If a Vitron tipped needle, look for white residue around the cone that sets in the seat. That is residue from gas sitting ther, can stick a needle shut, esp. with ethanol in the gas.

Sometimes the brass hinge pin can hang up, after adj. the float to 15/64" so be sure the float can move freely. But not too freely , side to side, as the float can hit the side of the bowl.

Check the float isn't compromised with a leak.

Using the Service Manual method of inverting the carb, allows float to hit the needle, and test with suction from the mouth. Light suction and a well seated needle will stick your tongue to the elbow. When you turn the carb over, the float falls free, and suction won't stick your tongue to the elbow. Of course, carb should be dry for this final test of float adjustment :D


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Re: Bad carb float again?

Post by Dan Hatch » Sun Mar 14, 2021 8:01 pm

I try to used gas without ethanol when I can.
Also, do yourself a favor and get one of Scott’s bigger size float valves and one of his installation tools. Dan

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Re: Bad carb float again?

Post by Steve Jelf » Sun Mar 14, 2021 11:00 pm

I've had Viton tips stick, but the trouble from that was fuel starvation, not flooding. I was lucky enough to get a few original needles in some auction plunder.


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Re: Bad carb float again?

Post by ivaldes1 » Tue Mar 16, 2021 12:08 am

I cleaned the valve with carb cleaner and wiped the needle thoroughly and that seemed to have fixed the problem. Remarkable that the fuel resistant grease must have traveled to the needle and stuck it open. Thank you for the help.


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Re: Bad carb float again?

Post by jiminbartow » Tue Mar 16, 2021 2:26 am

Dan, it looks like your gauge is upside down. Square side should seat against the flange and round side should face the float. The way you have it, there appears to be a gap under the gage on the flange side, which will make the gap wider than 15/64. Jim Patrick

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Re: Bad carb float again?

Post by ivaldes1 » Sun Mar 21, 2021 5:58 pm

I spoke too soon. We drove Shirley the 1922ish Model T touring to church. I turned it off waited about a minute and things looked good no leaking. I came out an hour later and it was leaking again out the throat of the carburetor but not as badly as before. There was a puddle of gasoline under her. Sigh, not out of the woods yet.
ivaldes1 wrote:
Tue Mar 16, 2021 12:08 am
I cleaned the valve with carb cleaner and wiped the needle thoroughly and that seemed to have fixed the problem. Remarkable that the fuel resistant grease must have traveled to the needle and stuck it open. Thank you for the help.


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Re: Bad carb float again?

Post by jiminbartow » Sun Mar 21, 2021 7:37 pm

How to about a new set of gaskets. If the carb is air tight, the fuel should not leak out and the gas should only flow when the engine is running and pulling in fuel. If air gets in anywhere, it allows the gas to flow. Sort of like when you stick a straw in a drink and put your thumb over the end and pull the straw out, the liquid will stay in the straw, but release your thumb and it all pours out. Jim Patrick


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Re: Bad carb float again?

Post by speedytinc » Sun Mar 21, 2021 8:22 pm

it dont work that way jimmy. under the nh tag is the air inlet for fuel mixture. it will pour out there or back thru the choke side of the carb.


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Re: Bad carb float again?

Post by jiminbartow » Sun Mar 21, 2021 10:00 pm

Actually John, that is how it works. When the float is adjusted right and the gas rises to the point of causing the needle valve to seal the inlet, preventing anymore gas from entering, the needle valve acts as the the thumb on the straw and keeps the gas from gushing out. If the float is adjusted wrong or the needle valve is not sealing properly, the seal that creates the vacuum that keeps the gas from flowing is broken and the gas gushes out. Good gaskets also create the necessary seals to prevent leakage. One of the tests that is done to determine if the needle valve is sealing properly is to suck on the fuel inlet angle fitting (#6203 in the drawing). If no air comes through, you have a good seal. If air comes through, you don’t. Without a good seal, gas continues to flow in causing the cup to overflow. Jim Patrick

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Re: Bad carb float again?

Post by ivaldes1 » Sun Mar 21, 2021 10:42 pm

So I need to do the vape thing with my carburetor? Seems a little embarrassing but I will try it.


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Re: Bad carb float again?

Post by speedytinc » Sun Mar 21, 2021 11:07 pm

"How to about a new set of gaskets. If the carb is air tight, the fuel should not leak out and the gas should only flow when the engine is running and pulling in fuel. If air gets in anywhere, it allows the gas to flow. Sort of like when you stick a straw in a drink and put your thumb over the end and pull the straw out, the liquid will stay in the straw, but release your thumb and it all pours out. Jim Patrick"

your answer here claims gaskets will solve the problem.

clearly, the problem is in the needle & seat.
If i am confused by your post, a hundred other guys that dont know any better may also be.
If the carb was air tight the bowl wont even fill. Submerse a drinking glass upside down in a bucket of water. Notice it wont fill. hense the breather hole to the bowl & the air inlet under the .id. tag on the other side of your diagram that is not shown or referred to. remove the needle & fuel will run out under the tag & out the choke side of the carb. like the problem described.


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Re: Bad carb float again?

Post by jiminbartow » Sun Mar 21, 2021 11:52 pm

Ignacio. See Dan Treace’s March 14, 4:18 pm post, figure 440. It was a common method found in the Model T Ford Service Manual that Ford recommended mechanics use to test the integrity of the needle valve. The suction should be so good that it will hold your tongue to the fitting. I agree John. The problem is most likely in the needle and/or the seat. Jim Patrick

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Re: Bad carb float again?

Post by Corey Walker » Mon Mar 22, 2021 1:49 am

You can turn the carb upside down, put the needle into the seat and spray soapy water all around it, then hold a little pressure on the needle with your finger and put a little air pressure to the fuel inlet and the bubbles will show if the needle is leaking or the gasket is leaking if bubbles come up between the seat and carb body.
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Re: Bad carb float again?

Post by speedytinc » Mon Mar 22, 2021 9:00 am

1.With the carb installed, drain a bowl full into a clean glass jar. (looking for dirt bits. can cause intermittent & temporary seating failure)
2. look at viaton needle for damage, nicks, off center tip & marks.
3. Do the suck test. (preferably with out the elbow to eliminate possibility of a slight leak there that will mess with suck test results.)
4. your tong should hole for a good minute.

I ran into a situation with some new metal needles. Restored a carb. passed the suck test. After a while it leaked. Reseated the needle (light tap to needle). Did another suck test. passed. turned needle 180 degrees. failed suck test.
Turned out that needle point was not machined centered. It was off more than the needle body & needle clearence.

So if carb passes the suck test, rotate needle to different positions & repeat.


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Re: Bad carb float again?

Post by FordFool » Mon Mar 22, 2021 6:35 pm

The Carb looks pretty rusty. I would go with the lead gasket under the seat. I’ve had that problem before.

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Re: Bad carb float again?

Post by ivaldes1 » Sat Apr 17, 2021 7:00 pm

I did the suck test. It is leaking at the elbow threads. I noticed when tightening the elbow more that the elbow threads are stripping. See picture, there is a dent in the threads at the entrance that is almost certainly stripping this out. I think the way to fix this is with a tap to realign the thread? Is there another way? Unfortunately my tap and die set doesn't seem to have the size this is. I think it is 24 pitch but unknown size.
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Re: Bad carb float again?

Post by speedytinc » Sat Apr 17, 2021 7:08 pm

thread is 1/8 npt. Taper pipe thread. Most sets have this tap. Being taperd, dont go to deep on the thread chase. Elbow thread looks stripped, needs replacing. Permatex aviaton or similar fuel resistant sealant works well.


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Re: Bad carb float again?

Post by Allan » Sat Apr 17, 2021 10:26 pm

The needle and seat are effectively a tap controlled by the float. As the float rises, so does the needle to close off the fuel supply at the seat. Job done.
If the "tap" still leaks fuel, the tap needs attention.

Allan from down under.

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Re: Bad carb float again?

Post by JTT3 » Sat Apr 17, 2021 10:37 pm

Ignacio I enlarged the picture and it appears by way over tightening it you may have cracked the the carburetor where it threads which you may never be able to repair. Don’t ask me how I know. The thread inside are tapered and the elbow will most always will have threads exposed. Trying to get the threads of the elbow even with the carb is instant trouble. If you look closely and there is no crack you’re lucky and may be able to clean it up with a tapered tap. If not order a new elbow and perhaps a rebuilt carb unless you have one to that you can rebuild yourself. You might contact Corey Walker he rebuilds carbs for sale.
Good luck, John
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Re: Bad carb float again?

Post by ivaldes1 » Sun Apr 18, 2021 12:04 am

As far as I can tell it isn't cracked, just the thread is damaged. My tap set doesn't seem to have a 1/8 npt. It has a bunch of other sizes. Home Depot and Walmart seem to have them 1/8 27 npt? Is that the right one? Mail order for about $9.
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Re: Bad carb float again?

Post by ivaldes1 » Sun Apr 18, 2021 1:23 am

Oh and olive oil mouth wipe and chaser after the suck test takes the gas and fuel proof grease taste out of your mouth quick.


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Re: Bad carb float again?

Post by kmatt2 » Sun Apr 18, 2021 1:52 am

You should be able to buy a 1/8 npt tap locally. Your old elbow to carb threads are shot. The new elbow will have to come from a T parts vendor if you don't have another good elbow. Use some gas proof permatex on the threads. You may want to get from the T parts vendor a elbow with shut off to keep from having to crawl under car to use the stock gas shutoff.


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Re: Bad carb float again?

Post by Allan » Sun Apr 18, 2021 6:29 am

Having to re-tap the thread in the carb body may be a blessing. Just clean it up first and fit the new elbow. If you have thread still showing, but the elbow is not pointing in the right direction, you can re-run the tap to let the elbow run in a little futher. It may take a few tries to get it to pint to the rear as it should.

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Re: Bad carb float again?

Post by TFan » Sun Apr 18, 2021 8:51 am

Ignacio, That tap set you are showing in your pic looks to have an 1/8 tap just below the thread check gage three down from the tap handle. That is more than likely the pipe tap. Hope this helps and good luck. Jim
Back road kinda guy stuck on the freeway of life.

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Re: Bad carb float again?

Post by ivaldes1 » Sun Apr 18, 2021 12:43 pm

Good eye Jim on the 1/8 if it was a snake it would have bit me!

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Re: Bad carb float again?

Post by ivaldes1 » Sun Apr 18, 2021 1:28 pm

So I ran the tap through and it straightened it up some. However, it still has a little spur on it that seems perfectly placed to shred the threads on a new fuel valve I happened to have. It seems to shred it less but you can see the ribbons of brass on it. I am not sure what to do next.
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Re: Bad carb float again?

Post by speedytinc » Sun Apr 18, 2021 1:39 pm

Possibly your tap bottomed out before you got the thread totally cleaned. Thats a feel thing. If thats the case, you can grind a little off the tap.


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Re: Bad carb float again?

Post by kmatt2 » Sun Apr 18, 2021 2:01 pm

If the modified tap doesn't work you can carefully remove the frist one or two threads in that area. Try using a deburing bit in your dremel and just slightly touch the thread.

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Re: Bad carb float again?

Post by RajoRacer » Sun Apr 18, 2021 2:27 pm

It appears the threads are already "buggered" up on your new shut-off as if it was cross-threaded. That type of valve is known for opening/closing issues after not too long of usage - Lang's has a very nice one but you get what you pay for !

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Re: Bad carb float again?

Post by ivaldes1 » Sun Apr 18, 2021 4:44 pm

The tap did bottom out. How much should I take off of the tap? The Dremel option sounds attractive.
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speedytinc
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Re: Bad carb float again?

Post by speedytinc » Sun Apr 18, 2021 5:23 pm

Just enough. start with that area where there are no threads. Remember it is tapered. go in only enough to clean the thread. You may have a 1/8 pipe die in your set. Kiss the elbow thread just enough to clean its thread also.


Allan
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Re: Bad carb float again?

Post by Allan » Sun Apr 18, 2021 7:43 pm

The tap in the photo does not look tapered to my eye, which begs a question. The thread on the fuel tap is tapered, so it would bind on the thread in the carb even if the carb thread was straight, but the engagement would be narrow. If the thread in the carb was also tapered, the engagement would be made through the length of the thread, making a better seal. Does anyone else see a straight tap in the photo? If it is straight, grinding some off the end would be fruitless.

Allan from down under.

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henryford2
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Re: Bad carb float again?

Post by henryford2 » Sun Apr 18, 2021 7:59 pm

For what it's worth the tap appears to be a BSP rather than a NPT. NPT/NPS and BSP threads are not compatible due to the differences in their thread forms, and not just the fact that most diametrical sizes have a different pitch. NPT/NPS threads have a 60° included angle and have flattened peaks and valleys (this is a Sellers thread form); BSP threads have a 55° included angle and have rounded peaks and valleys (this is a Whitworth thread form). Just my humble opinion. Enjoy
Always looking for vintage Whizzer engines, bikes & parts. What do you have?

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ivaldes1
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Re: Bad carb float again?

Post by ivaldes1 » Sun Apr 18, 2021 8:09 pm

Success! I Dremeled out the burr with a fine diamond tip. The burr turned out to be a sizable bump. It stopped shredding my elbow/valve thread. Suck test -- leak. Put some fuel resistant grease on the threads, suck test -- it held! Put the carb back on took it for a spin and let it sit for about an hour with the fuel valves on -- dry! Alright! let the fun begin. Thanks to all!

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