Marine engines are essential for shipping and global commerce, requiring proactive maintenance to ensure safety and efficiency. This guide outlines common engine issues expected in 2025, including overheating, low power output, misfires, exhaust problems, fuel delivery issues, electrical faults, starting air system problems, and oil leaks. Each section provides early warning signs, potential causes, and effective solutions. Emphasizing continual troubleshooting and leveraging technology is crucial for engineers to maintain vessel performance and compliance in an increasingly regulatory environment.