We found this pile of impeller blades while changing a cracked cooling water hose. The boat was new to Crowley's last winter. We changed the impeller in the spring and while the old one had cracked blades they were all still attached to the impeller. So, these blades have been floating around in this engine's cooling system for some time. We are amazed it ran without overheating. The lesson is to be sure that you get all of the blades out of the cooling system if you change an impeller that is missing any of them.