What should the compression be on a 4 cylinder mercruiser?

For a 4-cylinder MerCruiser engine, ideal compression values typically range from 140 to 160 psi per cylinder. However, it's important to ensure that all cylinders are within 10-15% of each other for optimal performance. If readings are significantly lower, it could indicate issues such as worn piston rings, valve problems, or head gasket leaks. Always refer to the specific engine model's service manual for precise specifications and guidelines.