Ensure your Yamaha 15FMH outboard engine maintains reliable cooling performance with this compatible impeller, designed to fit the water pump housing accurately and provide consistent water flow. The impeller is the core component of the engine's water pump, drawing water from the intake and circulating it through the engine to prevent overheating and maintain optimal operating temperature. Over time, impellers can wear, crack, harden, or lose flexibility due to regular use, seasonal storage, or running in saltwater, sand, or debris-filled conditions. Replacing the impeller as part of routine maintenance ensures stable cooling, reduces the risk of overheating, and protects vital engine components. With dimensions of 53 x 13 x 14mm, this impeller is designed specifically for the Yamaha 15FMH application, restoring proper water flow and engine temperature regulation. It is also interchangeable with Sierra 18-3040, providing an additional reference for compatibility. This makes it an essential service part to maintain efficient engine performance and protect your outboard from unnecessary wear.
Interchangeable with Sierra 18-3040
Designed for Yamaha 15FMH engines (53x13x14mm): This impeller fits the Yamaha 15FMH water pump precisely, ensuring proper seating and alignment within the pump housing. Accurate sizing is critical to maintaining effective water circulation and preventing leaks or restricted flow. Installing the correctly sized impeller supports consistent engine temperature and protects internal components from overheating during normal operation and high-load scenarios.
Essential for cooling system efficiency: The impeller draws water into the engine and circulates it through the cooling passages, keeping the outboard at the correct operating temperature. A worn or damaged impeller reduces water flow, which can lead to overheating, reduced performance, or damage to the engine's internal parts. Regular replacement restores proper function, ensuring the engine runs safely and efficiently during idle, cruising, or full-throttle operation.
Supports smooth operation and reliable performance: A properly functioning impeller ensures stable water flow, reducing temperature fluctuations and protecting the engine from heat stress. This leads to smoother running, consistent throttle response, and better overall engine reliability. Replacing the impeller proactively reduces the chance of unexpected engine shutdowns caused by cooling issues and helps maintain long-term engine health.
Ideal for routine maintenance and preventative care: Impellers are wear items that should be inspected and replaced regularly depending on usage, operating conditions, and storage practices. Frequent saltwater exposure or running in sandy or debris-laden water accelerates wear. Replacing this impeller as part of routine service helps prevent cooling failures and reduces the risk of costly engine damage, keeping your Yamaha 15FMH running reliably year-round.
Restores performance after storage or seasonal downtime: Engines that have been stored for extended periods can experience impeller blade set or reduced flexibility, which limits pumping efficiency on restart. Installing a new impeller before the boating season ensures reliable water flow from the first run, protecting the engine and supporting consistent temperature control throughout use.
Interchangeable with Sierra 18-3040 for reference: This impeller is compatible with Sierra 18-3040, providing a cross-reference for those familiar with aftermarket alternatives. While cross-references can assist in identifying suitable replacements, always verify dimensions and model compatibility to ensure proper fit and reliable operation in your Yamaha 15FMH engine.
Critical for engine protection and longevity: A functioning impeller protects the outboard from overheating, supporting stable operation and reducing stress on the powerhead. Replacing the impeller helps maintain reliable cooling, improves engine efficiency, and provides peace of mind during extended use. Proper cooling system maintenance is essential for safety, performance, and long-term engine durability.
Replacing the impeller in your Yamaha 15FMH outboard engine is a key maintenance task to ensure consistent cooling and protect the engine from overheating. A worn or damaged impeller can compromise water flow, reduce performance, and risk serious damage to internal components. With dimensions of 53 x 13 x 14mm and compatibility for the Yamaha 15FMH, this impeller restores proper circulation and helps maintain stable engine temperature under all operating conditions. Regular replacement is especially important after seasonal storage or prolonged operation in challenging water conditions. Installing a new impeller supports smooth operation, consistent performance, and long-term engine reliability, making it an essential component for any boating enthusiast or professional user.
Please refer to the image to ensure suitability.
What's in the box
1 x Impeller
