Get Mercury Merkur XR4TI Ignition Plugs Replacement & Mercury Merkur XR4TI Ignition Plug. Shop Mercury Merkur XR4TI Spark Plugs. Maintaining the optimal performance of your Mercury Merkur XR4TI hinges on the health of your spark plugs, a vital engine component responsible for igniting the air-fuel mixture. To ensure longevity, it's crucial to keep them clean and check for wear at regular intervals; signs such as misfires, rough idling, and a noticeable drop in fuel efficiency often signal the need for replacement. When selecting new spark plugs, consider options like copper for better conductivity or iridium and platinum for enhanced durability. Always opt for high-quality materials and adhere to the manufacturer's specifications for installation to maintain peak engine efficiency. Shop our selection today to find the perfect match for your XR4TI, and drive with confidence knowing your engine is firing on all cylinders.