that impeller was run dry, and or the boat run thru sh*tty water. check the tranny cooler as above. I doubt there is a water strainer. My impeller is on its 5th year and temp hold steady at 160- 166. It only runs dry at the beginning of the season start up till it sucks water. I have a strainer that has a bit of debris in it at the end of the season as i run in clear canadian water