Outboard motors work like just about any other small combustion engine. They intake air, mix it with fuel, add a spark, and it creates power that’s used to drive the propeller forward. Outboards have one additional element to consider though: water. They use water to cool the engine naturally, but also have to keep the water out of the other working parts—otherwise, the engine will break down and endure long-term damage. Unique engine hoses are required to handle all of these different liquids and substances, and to keep every part and piece separate from one another. Different outboards with unique designs will also require specific sizes and lengths of hose to operate properly. These different substances also require thicknesses for safety. For example, most water and exhaust hoses are 1-⅜”, while fuel hoses are 2”. This allows for appropriate efficiency and strength as they’re bent and flexed at different angles without cracking or breaking. Keeping all of the engine’s hoses in good shape is important not only to keep the outboard running well, but also to protect the environment from leaking fuel. A regular check of all of the hoses, as well as the clamps that connect them to different parts of the outboard, is easy and can keep an engine running smoothly. Use our Marine Engine Parts Selector Tool to find the right engine parts for your boat.