Check the impeller regularly and have a spare. Impellers are the heart of an engines cooling system and require regular inspection and replacement under normal operating conditions. Running through silty or sandy water or running a pump dry can ruin an impeller quickly and cause the engine to overheat. It is important to monitor cooling water outflow and replace the impeller at the first signs of reduced output. Sierra replacement impellers are engineered to meet or exceed Volvo Penta specifications to give boaters and technicians the confidence of an OEM fit and function. Because unexpected failures can happen, it is important to have a spare onboard to save the day. Key Features Impeller is engineered to meet or exceed manufacturer specifications OEM fit restores function and makes installation predictable Having a spare can save the afternoon and saves having to make a trip to the parts store. How to find the impeller you need Select your impeller by locating the OEM part number in the table below. If you don't know the OEM part number, please visit our Engine Parts Selector, where you can search by engine make, model, horsepower, serial number and year of manufacturer. ApplicationOEM Part NumberGLM21740Honda Outboard19210-881-A01, 19210-881-A02Mallory9-45100We offer a variety of Sierra engine parts for most engine applications on the water today—including MerCruiser, OMC, Johnson/Evinrude, Volvo and more.