Compact oil change electronic systems for fixed boat installations. Conceived for oil fill and drain operations for all on-board uses like generators, engines, transmissions and catwalks. Their electronic control adjusts the speed of the pump according to oil viscosity/temperature and increases its speed during priming. The system automatically shuts off in case of empty tank, short circuit and after 30 minutes of operation. OCS are indicated for a perfect cleaning of all on-board areas while avoiding leaks and dispersions on the boat floor.