How to adjust the cng mixture if it is too rich?

The performance of excessive mixture is that there is a sudden noise when the car starts. If it is too rich, listen carefully to the engine sound after starting or occasionally have a sudden sound. Then, after refueling, the mileage decreased, that is, it was not needed. The adjustment method is to find the pipeline at the outlet of the gas pressure reducer. The other end of this pipe is connected with the air inlet of the engine, which is easy to find. There is an adjusting knob on this pipe to adjust the intake concentration. If you can't adjust it yourself, I suggest you go to the master, because if the adjustment is too fine, the car will feel weak when driving, and it is not good to be too thick or too fine. The master of the gas modification plant can hear it with his ears, which is a matter of minutes. It is recommended to find a master to adjust.