I run boat in drive way and I got an overheat alarm. Work fine last time out. The boat is relatively new to me so I don't know the maintenance it's had. Thermostats and poppet valve are changed. I dropped lower unit and this is what I found
Seller likely demonstrated motor a number of times without water to the impeller.----That is done all the time !----The white piece likely has something to do with speedometer hose.