I believe if you will go back through this extremely long thread you will find multiple instances asking about the full flow of fuel between the tank and carburetor.
IF you have a flattened,kinked, crimped copper tube between the sediment bowl and the carburetor inlet, you have a restriction.
Take the screen out of the sediment bowl, line off the outlet side of sediment bowl, observe fuel flow. reinstall line at sediment bowl, remove line at carburetor, repeat - observe fuel flow. It should be the same.
5 to 10 seconds is not enough time to determine or evaluate your issue. sounds like you are running out of fuel.
Black spark plugs are indeed an indication of rich mixtures BUT you have only run engine very short times and at highly rich mixtures and low RPM. Plugs do not have a chance to heat up and burn the carbon residue off.

CTS

I can't recall talking about it but I'll try and get that spot back rounded. I have undone the fuel line and ran it not attached fuel flows fast but could still be restricted and I just think it's enough. I have run it for multiple minutes just mean 5-10 seconds before needing a quick hand over the intake and the fuel bowl is still full if I let it die and don't just close the fuel line and continue hand choking til it runs out of gas. 

The gas line was a s shape so I straightened it out got rid of the flattened spot since I shortened it by straightening it. That did not fix the issue. Kept it running long enough hand choking this time to spray carb clean on every part of the system from the tank, lines, exhaust, carb etc. Not an air leak anywhere in the system. I am now thinking I have to be measuring float height wrong, that is the only thing that I can see being the issue since I am certain passages are clean and clear. Someday I'll get this thing solved.

Good plan-I thought you adjusted the float prior.. When in there, check needle.
Sometimes the neefle will remain stuck shut when float drops which should typically allow needle to drop and allow fuel flow. Float raises with filling bowl, which pushes the needle up to stop flow. There may be an o-ring on the needle, but I doubt that’s the issue.

I have an IH 560 that after sitting a while I occasionally need to lightly tap its carb bowl with wood handle on a small hammer to shock it into opening. Not an uncommon issue or remedy.

I’m not sure if you’ve clearly answered if immediately after it dies how much if any fuel is in the bowl when you take out it’s drain plug. If bowl is full when it dies, float needle is likely functioning and problem may be in passages.
If bowl is empty, good chance needle is stuck shut. Maybe needle was replaced and not a good fit-

Not familiar with your carb itself, but seems I’m regularly messing with carbs on the few misfit machines I have and these are my experiences.

Look at the float mech and if I’m thinking backwards, just reverse what I’m suggesting while observing float and needle.

Good luck keep safe.

I have adjusted the float I am just left thinking I did it incorrectly. Fuel still in bowl after it shuts off not completely empty. I don't see any way the passages could be blocked. It's gone through many ultrasonic cleanings, torch tip cleaners, and carb clean shoots through every passage with ease after the rebuild. Main reason for thinking I may be measuring float wrong. It does move freely and the needle isn't getting stuck unless it only happens with gas but by hand it moves up and down easily.

-adjusting the float should not be that difficult, there is some wiggle room there...
-im getting a deja vu feeling all over again...
-after all this attention on carb and fuel...maybe your issue is spark...? ignition system?

-is the exhaust unrestricted? just another check...

it runs with your hand choking it. that means lack of fuel!!

so there is only a few things that cuase that problem.
the choke isnt working properly. i said about centring the choke and throttle butterflies if there not centred in the shaft and the bore the wont work properly.
the linkages can also be a problem. a way around that is to use aftermarket automotive choke cables or get throttle cables for a lawn mower and make some custom brackets to allow them to work

vacuum leaks from cracked manifolds, warped flanges, bad gaskets, worn shafts on the carb a smear of grease or a oring placed on the shaft can help the true fix is new bushings in the carb body. also check for warped flanges with a bit of float glass (poor mans surface plate) and a feeler gauge yes a gasket can take up a little unevenness but work best when the surfaces are "true" to each other. if you can slide a fine feeler gauge under the face when giving even down pressure on the flange it aint flat!

blockages in the carb it could be a tiny bit of shit that you cant see that moves with the fuel and causes the problem hence the suggestion to drill out the plugs and clean it fully.

is the mixture set properly. rough rule wind all the way in GENTLY then back it out 1/12turns works for most engines to get them running.

is it blowing smoke black is excess fuel blue is oil. black plug tips can be oil or bad plugs/poor spark or even the wrong bloody plug. a old trick with engines that foul plugs is to put a "hotter" plug in it. do a compression test bad rings will cause fouled plugs and low manifold vacuum if they dont seal properly. try new plugs of the correct type. (i had a engine that wouldnt run the plug seemed to work fine but failed when under compression.)

to eliminate the fuel line from the equation buy some fuel hose and a cheap inline filter and fit that in place of the hard line. also check the fuel tank for debris another member had problems with his not running turns out a bit of reciept paper was left in the tank from when he had it hot tanked at the radiator shop and he didnt know it was there. it was floating over the outlet and blocking it occasionally.

are you using fresh fuel? todays fuel is absolute rubbish and doesnt last longer periods. not a bigdeal in efi engines the computer adjusts accordingly carburettor engines cant do that.

yes if your setting the float wrong that could be a problem but as it runs when you choke it with your hand that means it getting fuel but not drawing it properly to run.

take the manifold off and check for cracks and warped flanges.
drill out the plugs on the carb and clean it again. replace the plugs with soft shot.
check for play on the shafts try the oring and grease trick it might fix it.

I did clean the tank, but I'll try it again. Fuel is fresh, I didn't get more gas until after I started working on it. With the new carb top shaft the choke is working properly and centered. I did 1 1/2 turns out on both adjustment screws, I will note the old top the idle screw went in way further. I was hoping that was the issue but it wasn't obviously. As far as cracks or uneven fitment, I'm pretty sure that all got ruled out by the carb clean spray test while it was running but I'll give it a look. I still need to do the compression test but I'm certain I have the right plugs and they are gapped per the manual. I have seen people say not to use champion plugs (after I bought those ones) but not sure that's the issue since spark is good. I do plan on testing with a rubber line and additional filter just need to go to the auto store this weekend. I'll give carb cleaning another shot as well but I've gone through it very thoroughly. Every time I pull it back off everything is clean and maintains good flow. If I have to drill the plugs again I'll need another rebuild kit. Might just try better plugs to start do another cleaning of the tank and carb and compression test. I wouldn't be surprised if the a ring was bad, they guy I got it from seemed to know it was going to need hand choked before we even started, so he must have known of some issue causing that.

One other thing I will add since you mentioned oil could have made the plugs black, the pony seems to be going through oil very fast. I put in fresh oil when I got it and it's already down to low. I can't find any oil leaks at the motor, it may be getting drained by the oil cooler leak, but I know the pony is only cooled when the diesel is on and I have had that turned over since getting it off the trailer. Might lend to the rings being bad theory. I'll get some stuff this weekend and go from there, once again I appreciate everyone's input.

The fuel line should come in the top not the "bottom"