When you’re rebuilding a 2-stroke Mercury V6, the center main bearing is one of the most important components for crank stability, smooth rotation, and long-term durability. The  Center Main Bearing is designed for builders who want dependable fitment and consistent tolerances in proven performance platforms.
 
This center main bearing fits 1991 to 2018 Mercury 2.0 Liter and 2.5 Liter outboards and supports a wide horsepower range, including 150, 175, 200, 225 Pro Max, 245 Carb, 260 EFI, 280 ROS, and 300 Drag applications.
 
Our manufacturer uses controlled metallurgy, consistent heat treatment, and reliable dimensional inspection. They publish quality information highlights structured quality management standards, listing ISO/TS16949 and ISO 9001:2008, which helps reinforce confidence for customers seeking an OEM-style approach to consistency and process control.
 
This 2.0 and 2.5 Liter Mercury center main bearing is manufactured to the exact sizing required for these V6 families, with an OD of 2.318 inches and an ID of 1.375 inches. Those measurements are critical when verifying crankcase and crankshaft fit during mock-up, especially in higher-output builds such as the 225 Pro Max, 245 Carb, 260 EFI, 280 ROS, and 300 Drag, where stable support at RPM is non-negotiable.
 
For correct planning and ordering, remember that two are required for each powerhead rebuild. This detail applies whether you’re refreshing a 1991 Mercury 2.0 Liter 150 or 175 or completing a full performance rebuild on a 1991-2018 Mercury 2.5 Liter 200, 225 Pro Max, 260 EFI, 280 ROS, or 300 Drag.
 
If you’re cross-checking your parts list, this bearing matches commonly referenced numbers, including 6440, 16440, 16756, 16756A1, 16756A3, 16756A6, and 9-51215. With the right dimensions, broad 1991-era fitment, and a quality-forward brand lineage, the SYI Center Main Bearing is a smart, confidence-building choice for Mercury 2.0L and 2.5L V6 powerhead builds.

Part Numbers:
6440, 16440, 16756, 16756A1, 16756A3, 16756A6, 9-51215, 16756A3
 
Contact Mike Hill at +1-714-697-1716 or email mike@buckshotracing77.com for technical support.