Mercury Plenum Intake - 8M0099004. The Mercury Plenum Intake (Part #8M0099004) is a factory-original replacement component engineered to optimize air distribution within your Mercury marine engine. Designed with performance and reliability in mind, this plenum-intake ensures that the engine receives balanced airflow for consistent combustion, efficiency, and throttle response.. Key Features. Genuine Mercury OEM Quality - Built to meet strict Mercury Marine standards for superior engine integrati