Fits Mercury Marine Thunderbolt HEI - V-6 engines. | Keep Your Mercury Engine Running Smoothly with Sierra's 18 series Tune-Up Kit Maintain peak performance and optimal engine health for your Mercury outboard with the Sierra IGNITION TUNE UP KIT. This comprehensive kit provides all the essential components you need to perform a complete and effective tune-up, ensuring your engine runs smoothly and efficiently for years to come. Why Choose Sierra's Mercury Tune-Up Kit • Genuine OEM Quality: Developed and manufactured to meet the same strict standards as original Mercury parts, you can be confident in the quality and reliability of Sierra's tune-up kits. • Comprehensive Kit: Includes all the necessary components for a complete tune-up, including spark plugs, filters, and other essential parts. • Easy Installation: Designed for straightforward installation, even for the do-it-yourself boater. Detailed instructions are included for a hassle-free process. • Improved Performance: Regular tune-ups with Sierra's kit can optimize spark timing, fuel delivery, and overall engine efficiency, leading to increased power and improved fuel economy. • Enhanced Engine Longevity: By replacing worn-out components and proactively maintaining your engine, you can extend its lifespan and minimize the risk of costly repairs. Investing in regular engine maintenance with Sierra's Mercury Tune-Up Kits is an essential step towards maximizing the performance, reliability, and longevity of your boat's engine. Order your kit today and experience the difference! | Includes 18-5396 Distributor Cap for Mercruiser Stern Drives (1) 18-5432 Rotor Assembly for Mercruiser Stern Drives (1)