Turning it in (leaner) the drop from right on the money to dying is pretty quick. So normally that's considered the best approach to adjusting the mixtures; turn in until rpm or vac just starts to drop and then turn it back an 1/8 to a 1/4 turn. It’s better to go back a little more because when the engine is put in gear it needs to be a bit richer to have power to turn the transmission.
