NAA carburetor still flooding

I posted about this a while back. I rebuilt this Marvel Schebler carburetor and it starts leaking fuel out of the air intake when I turn the fuel on. I have tried 3 different floats. As per advice on the previous posting I installed another new needle and seat and dropped the float level to 5/16. I installed the carburetor and it still leaked. I removed the carburetor, removed the float bowl and filled It full of fuel. No leak. I fastened the carburetor top upside down to the fuel line. No leak. It would flow if I held the float open. I don't see any cracks in the carburetor. The bowl gasket shows full contact so I don't think it is warped. I can hear the float move when I roll the carburetor over in my hands. The carburetor is cast iron. TSX 706. I have successfully rebuilt several of these Marvel Schebler carburetors. This one is kicking my butt.

If I have to replace the carburetor where is the best place to buy one? Would a Zenith be a better choice?

Thanks to everyone who has posted.

Arvin,Does your float have any gas inside of it?Remove it and shake it close to your ear and listen for sloshing.The float could be gas loged.

I checked for that earlier today. It was okay. Thanks.

Arvin, I remember your post from last week and thought you got some good advise. I think we are all missing the mark here. You have proven that the float and needle will shut off the gas at the seat. I would take the whole carburetor apart again and look for something you missed during rebuild. It sounds like the gas is flowing right out of the bowl and into the air horn. As for your question about a Zenith carburetor, I don't know. I've never been around one.

I've had a few cause me fits like that.
I didn't find the leak until I set the top half right-side up with the
floats in a glass jar, fuel attached, then watched for it to leak.
Sometimes the problem was that the seat did not seal to the carb
top half, even though it was tight. The needle and float were fine.
They did not leak instantly as soon as the fuel was turned on though.
It took them a few minutes to start leaking.

I bought an naa tractor still 6 volt. had trouble getting it to start. once it did it would run okay. I have never been able to rebuild a carb so I went on ebay. several places had the carb. I bought on for 58 bucks shipped t my house. would have probably spent 30 bucks for a kit. the old tractor starts right up every time. I have been told by a ford tractor parts place there all made overseas for these old fords. I did the same thing on an 8n I use to have. it worked fine also. that's just my experience hope it helps. good luck

I know the China clone carburetor issue is controversial, but at the price for a whole carburetor, it's worth considering. The rebuild kits are coming from China anyways. I've yet to put one on a Ford, but have fit several on Kohler one cylinder engines with a surprising rate of success. I too am frustrated with carburetor rebuilding, I've rebuilt 4 MS carbs in the last year and have had all of them on and off the tractors too many times to count.

Do you have a gasket on the float valve seat??

I had some give me fits too. I think its hit or miss with those Viton tip needles. I watched mine with the bowl off sometimes it would stick and other times it wouldn't. If you can get it where it wont flood while its running and operates fine I would just put a downline shutoff valve between the carb and tank. Does anyone have any solid brass needles they are willing to sell?

(quoted from post at 17:26:12 10/29/18) I had some give me fits too. I think its hit or miss with those Viton tip needles. I watched mine with the bowl off sometimes it would stick and other times it wouldn't. If you can get it where it wont flood while its running and operates fine I would just put a downline shutoff valve between the carb and tank. Does anyone have any solid brass needles they are willing to sell?

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Hope you have solved your carb problem by npw. Mine was the same. I found the replacement seat was too long and would not go all the way down. Checking tisco the only one they sold was too long. On ebay I found one that was shorter.

(quoted from post at 09:52:28 12/16/18)

(quoted from post at 17:26:12 10/29/18) I had some give me fits too. I think its hit or miss with those Viton tip needles. I watched mine with the bowl off sometimes it would stick and other times it wouldn't. If you can get it where it wont flood while its running and operates fine I would just put a downline shutoff valve between the carb and tank. Does anyone have any solid brass needles they are willing to sell?

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Hope you have solved your carb problem by npw. Mine was the same. I found the replacement seat was too long and would not go all the way down. Checking tisco the only one they sold was too long. On ebay I found one that was shorter.

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Bingo... good catch...

Now you can buy a brand new carb on ebay for 58 bucks with free shipping, its hard to shell out 60 bucks for carb kit. I try to rebuild them by just cleaning them and usually do ok as long I dont tear the gasket on the cleaning... but now I can get a new N series carb for 39 bucks and jubilee or 600 carb for 56 bucks, it pretty hard not to just order them instead of a rebuild kit.

I do see a lot of problems where the needle sticks in the seat housing due to the external_link gas goop. So I have to carefully clean the inside of the seat housing to allow the needle to move freely. I have also seen where the seat is too long and takes an extra gasket to make it seal.

Also have had a few where there something in a passage that I cannot clear, with cleaner, or air pressure, or with a welding tip cleaner.

So now more and more, if the first good cleaning does the job??, and by the second tear down cleaning, I ordering a new cheap, free shipping carb and move on the other problems with the tractor. In season all of the tractor will get to work in the field a bit before the final paint and clean up. Winter, not so much as they sit around like a bunch of women and look pretty.