OMC Evinrude Johnson O Ring

An O-ring in an OMC Evinrude or Johnson engine is a circular, rubber seal used to prevent leaks and ensure proper sealing between various engine components. They are typically made of Buna Nitrile rubber and come in standard sizes. O-rings are essential for creating a tight seal in hydraulic, pneumatic, and other machinery systems. Here's a more detailed explanation

Function 

O-ring work by being compressed and deformed when installed, filling gaps and creating a tight seal to prevent leaks

Material

While most are made of Buna Nitrile, they can also be found in materials like silicone or PTFE.

Applications

They are used in a wide variety of locations within the engine, such as fuel connectors, cylinder heads, trim & tilt mechanisms, and more

Importance:

O-ring are crucial for maintaining engine performance and preventing leaks, so they should be replaced when they show signs of wear or damage.

Identifying O-Rings

While they are often black, the color can sometimes indicate the material they are made of, such as red for Neoprene or blue for Fluorosilicone.