How long after cleaning the throttle does the exhaust pipe not emit black smoke?

Two to five minutes. The throttle is dirty, there is a lot of carbon deposit, and black smoke can be seen in the exhaust pipe. According to the dirty degree of the throttle, control this process for about 2 to 5 minutes. Throttle is a controllable valve that controls air to enter the engine. After the air enters the intake pipe, it will be mixed with gasoline to form a combustible mixture, and the combustion is successful.