40100-ZVL-020 Engine (Lower) Case - Overview. The 40100-ZVL-020 Engine (Lower) Case is a vital component in Honda marine engine systems. This lower engine case houses crucial internal parts such as the crankshaft and transmission gears, forming the core of the engine's lower section and supporting the engine system's mechanical operation. Engineered to maintain structural integrity under demanding marine conditions, it ensures seamless integration with existing parts, maintaining optimal perform