I got stupid last year and ran the boat
for at least 5 min at idle with the seacock closed.
No damage, there was water in the pump I’m sure but no water flow. This is a stock Yanmar
impeller, not any kind of special dry run impeller.
Makes one wonder if the ones that have problems if the pump is above waterline line and drains dry after every shutdown.
Something jammed that impeller I believe, like maybe the blades were bent backward and with no lube they stuck hard enough so the the inner liner was peeled away? Or the liner was only partially bonded to begin with?