Remove the throttle, there is a layer of oil at the air inlet of the engine. The attached picture is made by the master.

Hello. First of all, I admire you for cleaning the accelerator yourself at home. At present, there are many cleaning throttles, and vehicles need to be matched. There's a lot of throttle, if you don't understand. You can wash it yourself. There is oil here, usually the crankcase ventilation system, because the crankcase ventilation valve brings the pressure of the crankcase into the nearest air pipe. It's gasoline engine oil brought here. I suggest you check this pcv valve. I hope it helps you.