Carburetor float help!!

I have a Farmall 350 that has a carburetor that decided to start flooding out the engine about a month ago. In other words if I don’t shut off the fuel line to the carburetor in about 2-3 minutes there are puddles in the bottom of my intake air line and the tractor will not start.

In my attempts to do things right I took the gas tank off and cleaned it out, replaced both filter elements (at the sediment bowl and at the carburetor), and took apart the carburetor and cleaned it out. When I tore apart the carburetor I installed a new float needle and float seat along with all new gaskets. I also checked the float for leaks (the carb bowl was full of gas for 5-6 days before I disassembled the carburetor and there was no liquid inside of it). I checked the adjustment on the float and it was at 1 5/16” and also insured that the float was not rubbing on the walls of the bowl (the archives were very helpful).

Yesterday, after purchasing a new throttle adjustment needle (because the old one was bent) I put everything back together, turned on the gas, and started it up. It ran, but it ran extremely rich, which is understandable because I hadn’t adjusted the needles yet.

I shut the tractor off and quickly installed a new temperature gauge so I could be sure that the engine was warm before I adjusted the carburetor. Two minutes later I tried to restart the tractor unsuccessfully and discovered that once again the carburetor flooded out. Cussing silently to my tractor (I just had my first kid, a five week old girl, so I am working on becoming G-rated) I tore into the carb, and found that everything was exactly as I left it.

I believe I have gone as far as I can with out enrolling the help of the experts and less frustrated individuals. Does anyone have any suggestions on what to test or try next?

Thanks in advance, your responses are always helpful.

Andy

Make sure the float is not binding on the float pivot pin.

Tommy

1 – With the carb still on the tractor remove the float bowl. Lightly lift the float with one finger (to close the needle valve) then open the fuel shutoff at the sediment bulb. If any gas appears the problem’s somewhere around the needle valve. Look for a defective needle or seat, junk caught in the needle valve, bad or missing gasket ring under the valve seat fitting, or possibly a crack in the casting where the seat screws in.

2 – Now let the float drop with the shutoff valve still open. Gas should run freely from the float needle valve. Lifting the float again should immediately stop the flow.

3 - If the above checks out, reassemble the carburetor then remove it from the tractor. Invert the carb and shake it up and down. You should hear a distinct rattling as the float moves inside. If you hear nothing the float’s binding somewhere – you’ll need to remove the bowl find it. Or with the carb inverted, apply light and gradually increasing air pressure at the fuel inlet. At low air pressure (5 psi or less) you should hear nothing. However as pressure increases at some point you should hear a hissing or farting sound from within the carb as as air pressure lifts the needle & float. (I applaud your commitment to your new daughter for your use of “G” rated language, but I cannot think of a G-rated term which more accurately describes the sound!). Anyway if you hear air escaping even at low pressure, it again indicates a float bind. Look for a bent or distorted float hinge, bent float arm, etc.

Good luck and post back what you find!

Let me now add: To check the float for leaks dip it in a container of hot water. Even the smallest pinhole will show itself as a series of small bubbles. The bubbles will issue from the bad spot briefly as the air inside the float warms up.