🏷️ Basic Information Identification Make: Mercury Division: Mercruiser Product Name: PCM 555 Big Block Diagnostics Model Series: PCM 555 Diagnostic System: PCM 555 Engine Family: Big Block Serial Number Prefix: 0M Serial Number Designation: 0M000000 and ABOVE Covered Models Sterndrive Models: • 496 MAG HO • 496 MAG Inboard Models: • 8.1S HO • 8.1S Horizon 📋 Manual Details Publication Manual Type: Diagnostics and Troubleshooting Manual Manual Number: 33 Language: English Content Structure Section 1: General Information Section 2: Troubleshooting Section 3: Wiring Diagrams ⚙️ Engine Specifications Engine Type Engine Configuration: V8 Displacement Displacement Liters: 8.1 Displacement Ci: 496 Performance Power Variants: • HO (High Output) • Standard • Horizon Fuel System Fuel Injection Type: MPI (Multi-Port Fuel Injection) 🔧 Transmission Drive Type Sterndrive Options: • Bravo One • Bravo Three Inboard Options: • ZF Marine Transmissions • Velvet Drive 🔧 Maintenance Diagnostic Tools Required Diagnostic Tools: Mercury/Mercruiser Diagnostic Software and Interface