Appreciate some input on spark plug reading

Newbomb Turk said

Your bullshit arguement is that this engine is really rich but it’s lean at the plug so they have no color.

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I'll say it again: I can change 1 variable and it will make the plugs read REALLY RICH when I haven't changed the AFR at all. The can go from Tan before to Black after and I haven't touched the carb.

Its still metering the same Air and Fuel mixture but its now Rich.......Or is it?