What to watch out for after an engine overheat

As Capt J said, make sure you find the pieces of impeller, likely at the heat exchanger inlet.

Impellers rarely just go poof unless obviously you sucked smothering big enough to block the water intake.

Usually the alarm sounds before damage occurs but the coolant .getting out raises a red flag.

After how much time running did it overheat?

Reason I ask is that a couple of times, I ve had an issue with the raw water pump not priming itself which is unusual for a pump of that type. The first time, the cause was a corrosion hole, about 2mm, in the fuel cooler outer casing which in these engines is before the raw water pump.

Another time it was because of sea grass and debris having passed thru the strainer over the years and restricting flow at the fuel cooler inlet.

Another thing, is that usually when your impeller gets worn, or have any restriction in the flow, you will first notice a increase in transmission temperature, way before the engine coolant starts going up.

Finally, you may need to check the big exhaust rubber hose between the engine exhaust and the fiberglass exhaust tubes. If you lost raw water flow, chances are the hoses may have been damaged by the hot exhaust gases