This manual covers the Mercury Mercruiser 181 CID engine, an inline 4-cylinder gasoline engine with a 2.97-liter displacement. Designed for inboard and sterndrive applications, this engine is known for its robust engineering and reliable performance on the water. Its versatile configuration, compatible with various transmission options like Alpha One and Bravo, makes it a popular choice for a range of marine vessels. This manual provides comprehensive details to ensure optimal operation and longevity of your Mercruiser 181 CID engine. The purpose of this Full Service Repair Manual is to provide essential information for the maintenance, repair, and troubleshooting of your Mercury Mercruiser 181 CID engine. It includes detailed procedures for routine servicing, such as oil changes and filter replacements, along with technical specifications, fluid capacities, and recommended maintenance intervals. Whether you are a boat owner performing basic upkeep or a professional technician undertaking complex repairs, this manual serves as an authoritative resource to keep your engine running efficiently and safely.