All Holley Marine Carburetors are designed to meet Coast Guard specifications. A marine carburetors fuel metering system is calibrated to compensate for unique engine loads found on boats. The J-style vent tubes direct fuel/fumes back into the carburetor for safe operation while on rough waters. The Holley 080492 Marine carburetor is designed for OMC and Volvo Marine 4.3L V6 engines.