Accelerator pedal feel - stiff when car is hot

[Radioactive Man]

There is always something isn't there?

Since the car is back from paint repairs went for a run yesterday and when cold the accelerator pedal is nice and smooth, easy to press.

As the car gets hotter then the pedal becomes stiffer and feels really notchy and not easy to modulate.

I cant see anything obvious, the cable feels free and not binding if I disconnect the cable from the throttle linkage.

Is it possible that something on the carbs is binding due to getting hot?  I cant see anything obvious but the pedal feel is changing to the point its not pleasant to drive when hot.

Thanks in anticipation for any good ideas.