Indmar Water Pump Impeller
If you operate your boat in shallow, silty or sandy conditions we recommend that you inspect your boats impeller more frequently to ensure your boats cooling system continues to operate correctly.
It is recommended that you change your impeller annually or every 100 hours (whatever happens first) and keep a spare in your boat. Natural wear and debris in lake water tear away at your impeller, eventually to the point where the raw water pump can't keep up with the heat output of the engine. This leads to engine overheating which can lead to engine failure.