1936 A leaning out on Rapid throttle opening

My Brother and I have just completed a rebuild of 1936 A, Installed New higher compression pistons 0.090 over, new Rings, complete valve job, Johnson cold gas
manifold and a Rebuilt Magneto, new wires and plugs. I have cleaned the Carb (DLTX18)and unclogged all the idle passages with appropriate size drill bit from
Roberts Carb.
The tractor starts ok and idles well, on both low and high idle. We have not yet been able to load it to set the load mixture (currently set one turn out)

The only issue we have is the engine bogs down on rapid opening of the throttle. It is definitely going lean, as we can apply about half choke and get the engine to
accelerate smoothly.
The main nozzle was pulled, cleaned and reinserted. All other passages (that I could find) were blown out.

I have checked the float level, but want to verify this again. I suspect that the accelerating well is not filling up, but cant confirm.

Just looking for any other ideas?

Open the load needle till it accelerates properly. Ron Mn

Properly set, just ONE click is enough to make it Flame-out on quick acceleration..

Set Power screw with engine running at full throttle..open till you see clack smoke, close until the smoke goes away and it should be very close..

Idle, should be set as lean as possible..until the engine Flames-out on acceleration..then open only one click at a time until it operates like it should..

Thanks for the tips, will be doing some more work on it this weekend, will pass on results

Are you sure the air passage at the bottom front of the venturi is open?

Look in past the open choke & make sure the hole drilled front to back through the shoulder of the venturi at the dead center bottom of the carburetor bore is open. If that air passageway is NOT open, the acceleration well of the main fuel nozzle & all it's passages won't work. It will fall flat on his face when you go from idle to WOT.

Air going IN through this passage is what pushes the fuel out of the acceleration well giving it the shot of "extra juice" it needs at sudden large throttle openings.

I doubt the acceleration well not filling to be the problem. The well fills through the load needle passageway. If the float level is OK the engine would not run on the load circuit if it was so plugged that the well could not fill.

If you've had the main nozzle out, I'd be more suspicious of it being the wrong nozzle or not being fully installed. If one of the large diameter cross sections of the main nozzle is partly or maybe completely blocking the air passage mentioned above, the well won't work properly.

The acceleration well will work as long as it is the right one and it fills (because of adequate float level), the side holes are open & the forward air passage is open enough to let air rush in replacing the fuel that collected in the well at low throttle settings.

There is quite a variety of those nozzles.

thanks for all the ideas. I found the problem today, Even though I had soaked the carb and cleaned all the passages, it then set on the bench for several months before being reinstalled.
I pulled the carb today and checked all the passages again, pulled the nozzle, and it was clear.

What I found was that a small dab of rust had formed underneath the load needle and pretty much blocked the flow into the accelerating well.

Once I cleaned that and put it back on the tractor, I set it 3/4 turn out and it ran fine, no stumbling on acceleration, I get a quick puff of black smoke, then it settles down.

I'm sure it could be fine tuned, but all I could do was run up a pretty steep hill in high gear. The tractor pulled with no problem.

The goal this year was to get it running correctly, now that thats done, next summer will be the clean up and paint.

thanks again