This made no sense to me whatsoever. Given the number of accolades this was getting, I pinged a friend who consults to one of the major marine propulsion manufacturers (including generators). Granted, he's talking propulsion engines, but I don't see a huge difference on all counts except the first comment on pump continuing to run after engine shut down (even then, you'd have to ensure the pump isn't energized by the inverter). BTW - replacement OEM pump for my Northern Lights 6kw is $220.
I'm sorry, to me, this just looks like a solution in search of a problem.
Here's his response:
I have substituted an electric pump for an impeller pump on a propulsion engine twice in an emergency but it is a very easy way to fill an engine with seawater if the flow doesn’t stop immediately when the engine shuts down. It is also very difficult to get anything resembling a good flow match for the cooling system, since the flow isn’t linear with engine RPM, like an impeller pump. At higher loads, when exhaust back pressure is higher, the flow of a centrifugal pump drops dramatically, just when you need the most cooling. So, yes, it sort of works in a limited way but also comes with some seriously engine life threatening caveats.