What is psi compression on 1978 evinrude model 115899c?

Psi compression on the 1978 Evinrude model 115899C refers to the pressure measurement in pounds per square inch (psi) within the engine's cylinders during a compression test. This measurement indicates the engine's health and efficiency, with typical compression readings for a well-maintained outboard motor ranging between 90 to 120 psi. Low compression may signal issues such as worn piston rings or cylinder damage, affecting engine performance. Regular checks can help ensure optimal operation and longevity of the motor.