Is this carbon buildup? And how can I fix this?

MOPAROFFICIAL said

Only 2 listed are even relevant to the sooty carb. He would have to be driving the crap out of it while in that condition to look like that..

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Post 1, third sentence. It pops when he steps down on it.
To me that means a back fire thru the carb. That will build carbon deposits from the cylinder to the air cleaner faster than you can imagine.