A.P. Baltimore, MD

Q: After I swapped carburetors on my 307 Chevy, I noticed blue smoke coming out of my car’s tailpipes when I accelerate. I always thought too much gas caused blue smoke, and white smoke was oil or transmission fluid burning. Am I correct and can you tell me what’s causing the blue smoke?

A: Generally speaking, blue smoke is a byproduct of burning oil, and excess fuel will produce black smoke. Of course, water turns to steam when it gets hot and can be mistaken for white smoke. If your engine was not burning oil before the carb change, I suggest you check all of your vacuum lines. It’s possible one is hooked up incorrectly and that’s letting some oil enter your intake when you accelerate.

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