This service repair manual provides comprehensive information for the Mercury MerCruiser #36 ECM 555 Diagnostics. Designed for maintaining and servicing this specific Engine Control Module (ECM) system, it ensures the MerCruiser remains in top operating condition. The manual is a valuable resource for understanding the intricacies of this marine propulsion diagnostic tool, reflecting the engineering quality and reliability expected from Mercury MerCruiser products. The scope of this English-language manual covers essential maintenance procedures, detailed troubleshooting guidance, and technical specifications. It includes step-by-step repair instructions, disassembly and assembly procedures, inspection and adjustment protocols, and is supplemented with helpful photos and illustrations. Furthermore, it provides crucial wiring diagrams for ECMs with both 10-pin and 14-pin harnesses. This manual is intended to empower owners, mechanics, and technicians with the knowledge necessary for effective upkeep and repair.