Mercury - Repair Kit Engine Maintenance & Service Precision Components 854256. Overview. Every seasoned boater knows that smooth days on the water depend on one thing - keeping your engine in top shape. The Mercury 854256 Repair Kit gives you the confidence that comes from knowing your motor is ready for anything. Whether you're prepping for the first run of the season or fine-tuning your setup after a long weekend on the lake, this kit includes the right parts to restore performance, reliabilit