Yamaha - O-Ring Cooling System Seal 6EE-G4311-00-00. Overview. O-rings might be small, but they can cause big problems if they fail. I've seen simple seals like this lead to leaks or cooling issues, especially on smaller motors like the F2.5 where everything is compact. It's one of those parts you always replace while you're in there-it's just not worth reusing. When it's fresh and seated right, the system stays sealed and trouble-free.. Key Features. • Reliable Seal Performance - Helps prevent leaks within cooling system connections.• Flexible Rubber Construction - Designed to maintain a tight seal under pressure and temperature changes.• Compact Precision Fit - Matches Yamaha specifications for proper seating in tight spaces.• Heat and Water Resistant Material - Built to handle continuous exposure to engine heat and water flow.• Direct Yamaha Replacement - Ensures proper sealing and dependable operation.. Engine & Boat Compatibility. Designed for Yamaha F2.5 outboard engines requirin