As with most engines, there is no one "right" spark plug for a Briggs and Stratton engine. The best spark plug for your engine will depend on a number of factors, including the type of engine, the operating conditions, and your personal preferences. One important factor to consider when choosing a spark plug is the heat range. The heat range of a spark plug indicates how much heat the plug can dissipate before it becomes too hot. If the plug is too hot, it can cause pre-ignition and engine damage. If the plug is too cold, it can cause fouling and poor engine performance. Another factor to consider is the electrode material. The most common materials are copper, platinum, and iridium. Copper is the most economical choice, but it wears out quickly. Platinum and iridium are more expensive, but they have a longer lifespan. Finally, you'll need to decide on the gap size. The gap size is the distance between the tip of the spark plug and the ground electrode. The correct gap size for your engine will be specified in the owner's manual. When choosing a spark plug for a Briggs and Stratton engine, it's important to consider all of these factors. The best way to find the right plug for your engine is to consult with your local Briggs and Stratton dealer. They can help you choose the right plug based on your specific needs.