Exhaust pipe color

Black is too rich, chalky to white is too lean, tan is about right, but since we have air cooled engines, I would run more to the rich side.

The tan color is indicative of an engine running leaded fuel “Avgas”.

The black sooty deposits are from running auto fuel. Look at the tail pipe of your car.

Anyone have opinions about the engine condition that produces a chalky vs black exhaust pipe interior? I seem to remember that
a whitish exhaust pipe (not smoke) suggest good engine condition, but most of us have black. Thoughts?