1942 D4 carburater repair for pony

I am assuming you mean it sticks and floods the engine? Does it do this while running or just drain the tank into the oil after you shut off the pony motor? It's very common for the tank to drain into the oil even with a properly functioning carburetor float and valve, so the recommendation is to always stop the pony motor by shutting off the valve from the tank and let it burn all the gas it will suck out of the carburetor bowl before it stops.

If it floods while running and If the tank and lines between it and the carburetor are clean, go ahead and buy the kit! If not, clean them first and see if not having a steady supply of trash to lodge in the needle and seat will help.

Is your float in good shape? Adjusted properly?

You might also want to take a real close look at the carb's inlet valve and seat. It there's roughness or dirt in/on either, it can cause a problem. If the needle valve is the rubber tipped type and the rubber tip is missing or worn, there's the cause. If it's solid brass, look for small flat or worn spots about 1/16" from the tip.

If you've tried cleaning it and it still sticks, the only other option is to replace the needle & seat. Don't forget to check the float for leaks also. Sometimes the float will get a small crack or pinhole and partially fill with fuel causing the needle to not close completely. Clean the float and shake it, if there's fuel in it you will feel it and maybe hear it too. Shaking it will also build a little pressure inside the float so you can find the leak. Fuel can be removed by blowing air into the pinhole and holding the float with the pinhole to the bottom so the fuel will drain. Brass floats can be repaired by soldering the pinhole but be extremely stingy with the solder because it will add unwanted weight to the float. I usually solder the hole and immediately wipe off most of the molten solder with a rag.
Good luck!

When I rebuilt the pony carb on my D2 5U12142 it was flooding and I assumed the float had a hole in it and was holding the needle down but to my surprise the float is made out of cork, is this normal? it seems to work fine once I cleaned out the many years accumulation of crud.