I remember once working on a car that was wet from the rain. I was leaning over this wet fender with my sensitive part resting there. I was setting the timing & when I grabbed the dist cap to turn it spark from a bad wire insolation went into my hand & out through the sensitive part as that was the path of least resistance.Before vacuum gauges were in my hands I would take the most sensitive part of my body and rest it against the fender and adjust the mixture screws.
You may have been kicked or racked in those things. Rest them on the fender and start adjusting the carb.
Max Vacuum is not always the best way for best performance.
But does not hurt to mess with things that is a fact.