Engine runs way too rich!

[DRG-ler]

Hello guys, I have a new question.

My Ford runs well, starts well, but runs way too rich! The consumption is 18L/100km. My uncle also drives Model A, which consumes between 8L and 10L/100km. Well, the consumption always depends on the driving style, but I think 18L is clearly too much.

It also shows that the spark plugs are black. There is also noticeable soot deposits on the valves, pistons and behind the exhaust end.
I'm trying to reset the carburetor now. Does anyone have instructions on how to reset the carburetor? Maybe a youtube video too?

I also noticed that the engine makes a noise while driving that is reminiscent of a broken manifold gasket. I have already replaced these, along with a new exhaust manifold. This was planned together with the intake manifold by the engine builder. So this one is definitely closed.

I suspect that maybe a valve is no longer closing properly. That would perhaps also explain the slight backfire in overrun mode. A device for a pressure drop test is on its way to me. I think that could also be a reason for the high fuel consumption.

Greetings Andy