Could be the winter fuel. But low in the bowls should have been a slightly leaner mix if anything. Do you have a fuel pressure gage you can mount on the cowl?
I have one but don't usually leave it on the car. its not waterproof (and draws extra attention that not always a good thing)
It sits in this location.
View attachment 1715509616
The steel tubing gets held under the black backet atteched tothe the washer nozzle screw.
Red strap hold s the gage to the cowl.
AN-line goes to a tee in the carb feed. AN cap when not using the gage.