Ferguson TO20 carborator and manifold repairs

I have a Ferguson TO20 from the 1950's. I purchased a new carborator and installed. It ran great. Then I thought I would replace my exhaust manifold because it was cracked and loud. After installing I can't get it to run properly. Gas runs out of the carborator and blows into the air filter. Any ideas to help me out?

Hello TT welcome to YT! What has likely happened is
some small particles came dislodged from the fuel line
or the fitting connection and are interfering with the
sealing of the float needle valve in your carb. Try this
turn off the gas at the tank and run the tractor till it
stops. Get something like a pliers or 9/16 wrench to
rapidly tap on the top of carburetor near where the fuel
line connects. Quickly open the fuel valve and begin
the tapping for about 10 - 15 seconds. By doing this
the float drops opening the float needle as far as it
can. The quicker flow of fuel refilling the carb bowl assisted by the vibration
of the tapping hopefully flushes the particles out of the
sealing area hopefully allowing it to seal properly when
the float closes the valve. There is a possibility that it
may not work and the bottom will need pulled off the
carb and the debris physically removed. If this
continues checking the cleanliness of the entire fuel
system and if the proper screens are in place may be
required.
It so happens that this Restoration and Repair Tips
forum does not get the highest amount of views. Just
FYI the ..Tractor Talk.. forum is sort of a general repair
topic section which is probably a better place for these
sorts of questions. There is also forums dedicated to
machine per manufacturer, such as there is one for
..Ferguson.. tractors. If you cannot figure out how to
find the other forums or topic sections here is a little
info on that. Depending what ..View.. you are in if you
use the ..Jump to.. or ..Hop to.. drop down box seen
below when viewing your post you can navigate to
those topic sections. Clicking in them will bring up the
..Topic section.. list for you to choose from. There are
other ways to navigate to the other topic sections. If
you hang around here long enough you will figure them
out. This method seems to me to be the easiest to
explain.

Thank you for the prompt response.
I shut off the fuel, emptied the bowl of the carburetor then turned the gas back on while taping on the carburetor and it started and ran backfiring thru the carburetor occasionally. I figured I'm on the right track. I took the bowl off and looked for any obstruction in the float. Now the float seems stuck open all the time.
Not sure if the needle is seating correctly but I will keep at it tomorrow.

Thank you again.

Now pull out your spark plugs they will probably be
black and sooty from operating in an extreme rich fuel
mixture. The carbon in the soot residue will not let
them fire properly. Replace them or clean them, clamp
the in a vise tip up, spray with carb cleaner, wire brush
trying to get the wires down in around the porcelain
cone. Then blast it with compressed air holding a rag
over it to contain the nasty carb cleaner. Then repeat a
second time. Should have told you about the plugs the
first time cannot always remember everything. If I was
standing there the minute it started and run bad I
would have remembered.

I worked a bit further on the tractor yesterday. I cleaned the spark plugs up as recommended. At this point its running perfectly except for a constant pop through the carburetor as if a spark plug fouled? I'm going get new spark plugs and hope that helps.
Thanks for all your help. Really appreciate it.
This tractor was purchased new by my grandfather in the 1950's and used on his farm. Then passed down to my father. Now both have passed and I use it for snow plowing. Sentimental valve.

Thank you