Yamaha - Check Valve Kit Fuel System Control Component 7DH-R4104-00-00. Overview. Check valves are one of those parts you don't think about until fuel starts draining back or the engine takes longer to start. I've run into plenty of cases where a weak or stuck valve caused inconsistent fuel delivery without any obvious leaks. This kit helps keep fuel moving in the right direction and holds pressure where it should be. When it's working right, starts are quicker and the system stays more stable.. Key Features. • One-Way Fuel Flow Control - Keeps fuel moving in the correct direction to maintain system pressure.• Improved Starting Performance - Helps prevent fuel drain-back that can lead to hard starts.• Complete Kit Solution - Includes necessary components for proper replacement and service.• Reliable Internal Sealing - Designed to reduce leaks and maintain consistent fuel system operation.. Engine & Boat Compatibility. Designed for Yamaha outboard engines that utilize check valves withi