Mercury Racing installed four (4) water diverters in the High-Performance (Bridgeport, 245 Carb, 260 EFI Offshore, 280 ROS,  300 Drag, S3000, F1) V6 2-Stroke Cylinder Blocks using sized rubber hoses to optimize the cooling efficiency.
 
Retention Time: The cooling system needed to maintain a specific "retention time," ensuring water stays in contact with hot surfaces long enough to absorb heat effectively. The water diverters and restrictor washers, which replace thermostats, help control this flow, preventing overheating or excessive heat transfer back to the engine components.
 
Flow Control: Rubber hoses and restrictors precisely control water flow around the cylinders, maximizing heat absorption and preventing air bubbles that could disrupt cooling efficiency.Air Bubble Prevention: Proper hose design and placement ensure a smooth, continuous flow of water, minimizing the risk of air pockets that could create hotspots and compromise engine cooling.
 
Water Diverted: These are strategically installed with specific gaps and orientations (e.g., starboard at 11:00 and port at 1:00) to ensure even water distribution and manage retention time, which is crucial for maintaining engine performance and preventing localized overheating.
 
Pressure and Flow Management: The combination of water diverters, rubber hoses, and restrictors balances cooling water pressure and flow, ensuring sufficient heat absorption without causing heat transfer back into the engine's metal components.
 
Cooling Solutions: Careful management of cooling flow is essential in every build, regardless of the motor or vintage. This approach is critical for optimizing the performance and longevity of high-performance powerheads including all 2.5, as well as 2.0 and 2.4 Liters.
 
The installation of water diverters leaving 1/8" gap front and back and orientated starboard at 11:00 and port at 1:00  as pictured, ensures that water flows properly around the cylinders. 
 
Use needle nose pliers, WD-40,  and rubber hammer to carefully install these in the proper locations.