10 btdc is standard you cant ajuster it?

10 degrees before top dead center (BTDC) is commonly used as a standard ignition timing setting for many engines, but it's not universally fixed. While some engines may have a specified timing that should not be adjusted, others can benefit from fine-tuning based on factors like performance, fuel type, and engine condition. Always consult the manufacturer's specifications for the particular engine in question to determine if adjustments are permissible or advisable.