You have the mower sitting in front of you.
We have the words you typed on the screen.
If the engine is missing find it :laughing:
If you have a problem you want help fixing, then a full description, starting with the model & code of the Briggs engine then every thing it does, what you see , hear, feel & smell
What you did to the engine last, what the oil level is, what the oil feels & smells like , how long has this been going on , is it getting worse, what grade of plug did you fit, how old is the engine haw may hours on it what type of yard do you have
As stated, you must give us more info. We have no ESP and aren’t standing next to you with a drink in our hands. For sure we need the complete model, type and code numbers from your engine. Then give us a better picture of what is happening and what you have done to resolve the issue. You must help us to help yourself.