Weber 42 DCNF accelerator pump inlet ball valve stuck

The Weber 42 DCNF carbs use two ball check valves in their accelerator circuit. One is at the accelerator jets and easily accessible/replacable. The other one is between the float bowl and the accelerator pump, see yellow in image below:

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The Weber manual says to shake the carb body to hear whether this valve moves freely. On one of my carbs, it doesn't.

Now my question: how do I solve this? There doesn't seem to be a way to unscrew this assembly to get to it, nor do I find a replacement part for sale. I can spray some carb cleaner into it from all sides, but I don't know if that will get it unstuck. Likely pieces of disintegrated membrane got stuck inside.

Looking into the float bowl I can see the top of this assembly, but it is flush with the carb body and has no slot for a screwdriver or anything. There is no lead plug on the opposite side to tap it out.

On the left side in the float chamber you see the yellowish top of the assembly (at least that is my assumption, it does not look like a lead plug):

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When you disassemble the accelerator pump, you get access to a a part of it (the orifice and the part above the ball) but not the actual ball. I have not yet tried compressed air to get it to move. I'll try that when I get to it.

I'm also looking into buying an ultrasonic cleaner, that might help things too. These carbs are dirty and I'd like to get the passages clean without drilling.

 

I'll try that if carb cleaner and ultrasonic fail, as a last try before drilling out lead plugs.

As for the stuck ball, I'm afraid that membrane coating particles have gotten into it. Those are not dissolved by carb cleaner. Hopefully compressed air or the ultrasonic do the trick. I haven't made it to the garage yet due to horrific weather.

 

Compressed air finally did the trick! Normally you hate it when you hear a rattle in your car, but this rattle is most welcome. A clogged channel meanwhile is open as well. Just a clogged accelerator jet remaining as far as I know at this moment. That sounds like a job for the ultrasonic. MEK if that doesn't help. Worst case I could buy a new jet.

 

Does anyone here have experience with disabling the choke functionality on a DCNF? Do I need to do anything other than place a blanking plate instead of the double cog mechanism, leave all the rest (choke pistons) in place? I ask this because my particular manifold simply doesn't have the space for those mechanisms. Those Webbies will be sitting in a tight row!

As far as I could read, starting them without choke would amount to little more than pumping the gas about 3 times; the accelerator pumps should provide all the enrichment one could dream of?

 

I think I'd best install the mechanism blanking plate and blank starter jets to make 100% sure the choke circuit will never ever leak fuel.

In this case, I think I should also leave the choke pistons and their springs installed, to prevent the carburetor from sucking air through the choke channel past the throttle plate?

This does simplify things quite a lot, and it avoids me spending time and money on a choke cable installation. ...at the cost of a handful of blanking kits.