...labelled "Fuel lean..." something something not quite legible.
The mixture control in the Cessna 150 is labeled 'Mixture' above the knob, and 'Pull Lean' below the knob.
Directly below the mixture control, on some models of C150, are the Cabin Air/Heat controls, which look quite like the Carb Heat. They are labeled 'Cabin Air' and 'Cabin Heat'
I think that it's one of these you are looking at.
With the passage of time, and fading of the captions, you are perhaps, mis-reading the 'Pull Lean' caption for 'Fuel Lean' and associating it with the knob below it, rather than the one above.
Hope that helps.
MJ
