Owners of Mercury 3.0L V6 outboards, including high-performance models like the 300 Pro Max, 300X, and other 3.0L carbureted and EFI models, often choose to remove the factory oil injection system to improve reliability.
While oil injection failure rates in the 3.0L engines are generally lower than in the 2.0L, 2.4L, and 2.5L models, some operators prefer the added security of pre-mixing fuel and oil to eliminate any risk associated with a failing oil pump.
This is especially common in higher RPM performance applications where precise fuel mixture control is crucial. To complete this modification properly, an oil injection block-off kit is required to seal the pump mounting location.
Our oil injection block-off kit includes everything necessary to replace the oil pump. The kit consists of a thermo plastic block-off plug (part numbers 43453, 43453T, 43453-1, 433531, 785211, 825-505K), a sealing O-ring (Mercury part number 25-32509), and two mounting screws (Mercury part number 10-41506).
Our kit is designed to fit a range of 1994-2001 Mercury and Mariner 3.0L V6 outboards with factory oil injection. This includes popular models such as the 225 HP, 250 HP, 300 Pro Max, and 300X, including 3.0L EFI and carbureted 2-stroke outboard engines used in both recreational and high-performance applications.
Installation of the oil injection block-off kit involves removing the existing oil pump and drive shaft, then inserting the block-off plug into the oil pump mounting hole. The included O-ring ensures a proper seal (we like to add thin layer of silcone around the oring area as well), and the provided screws secure the plug in place.
It is important to disconnect and seal all oil lines correctly to prevent any air from entering the fuel system, which could cause performance issues or engine damage.
This modification is commonly performed by those who prefer pre-mixed fuel to eliminate the risk of oil pump failure and ensure consistent lubrication, particularly in high-rpm applications.
This upgrade is widely adopted by owners of Mercury 3.0L V6 outboards, including the 225 HP, 250 HP, 300 Pro Max, and 300X, who prioritize reliability and performance. By switching to a pre-mix setup, operators gain complete control over oil ratios and remove the possibility of a sudden oil injection system failure.
Whether for offshore racing, bass boats, or high-speed recreational use, the oil injection block-off kit is an essential component for those looking to optimize and safeguard their Mercury 3.0L V6 engine.
For technical support contact Mike Hill at mike@buckshotracing77.com or call +1-714-697-1716