What is the compression in a mercury outboard?

The compression in a Mercury outboard refers to the pressure created within the engine's cylinders during the compression stroke, which is crucial for efficient combustion. Typically measured in pounds per square inch (psi), optimal compression ratiOS can vary depending on the specific model and type of engine. Generally, a healthy compression range for most outboards is between 90 to 150 psi. Low compression can indicate issues such as worn piston rings or valve problems, affecting engine performance.