What is the cause of carbon deposition in throttle?

The gasoline sprayed in the working cycle is not recovered, but only attached to the intake valve and the combustion chamber wall. Gasoline is easy to volatilize, but residual wax and colloidal substances will cause deposition. So far, these substances have accumulated to a very thick degree, and if they are heated repeatedly to harden, they will lead to carbon deposition. There are several reasons for carbon deposition in the throttle. First of all, due to various reasons, such as fuel quality or air quality, fuel combustion may be incomplete. Secondly, factors such as oil leakage from the valve, failure of the recovery system, poor road conditions, and slow vehicle speed may also cause the evaporation rate of gasoline sprayed on the back of the valve to slow down. Third, problems such as oil failure, cylinder pressure and water leakage at the bottom of the cylinder may also cause carbon deposition.