This Briggs & Stratton replacement spark plug RJ19LMC 799876 complies with federal EPA regulations in regard to emissions produced by your Briggs & Stratton engine. To maintain the health of your outdoor power equipment your spark plug should be replaced every year. Symptoms of a bad spark plug are your engine has a rough idle struggles to start misfiring of the engine surging high fuel consumption and lack of acceleration. If one of these is occurring your spark plug needs to be replaced. You will need a spark plug wrench to properly remove your old spark plug and replace it with a new one. To ensure a proper fit to your outdoor power equipment please reference your owner’s manual.