And what's going on here?

Top of other manifold with the gasket off tells me a bit more I believe on the age of these things….

water droplet maybe here it is off and clean.

That impeller is smoked...you can see the black rubber bits on the center of the plate....doesn't take much for them to start sucking air and you get steam pockets in the water system....also kinda looks like the center of it is "stripped out" for lack of better terms. Was it actually spinning or was the shaft spinning inside the impeller? Could just be the pic but that impeller is def an issue to me anyway, not saying it caused the issue but it is one issue. Possibly was sucking enough air/cavitating in the housing and the water flashed to steam in the header and POP?? Just a thought....

I don’t disagree! Also what another buddy of mine said as well! I took it apart tried to spin it etc I couldn’t get the center to spin but I do think it looks like that also.

luckily I think I did make an upgrade with these Hardin marine pumps

What fuel pump is that? It does not look like a Merc. Or did you strip the paint off of it.

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