Your issue is google searchable as "vapor lock"; but it's debatable as to whether or not it's the correct terminology - and you'll find an abundance of effective and ineffective solutions online.
I fight the same issue with my VP 5.0 carbureted engine - other's posting on this forum have discussed similar issues. My non-expert explanation is that your fuel has evaporated or boiled off in the fuel line between the pump and your injectors (no carb right?). The vaporization of the fuel creates a loss in feed pressure and/or positive pressure in the line and your fuel pump has to overcome this to deliver fuel. It seems the higher ethanol fuels have aggravated the problem.
Other guys here may suppose it's related to the fuel tank venting and/or the anti-siphon valve where the fuel line taps into the tank. The latter two causes can have less of a dependency on temperature - so i tend to dismiss those as a dominant cause.
For me, I've verified my fuel pressure is ok, insulated my fuel line, verified the tank vent and anti-siphon valve, change fuel filter, changed plugs, cleaned the spark arrestor and distributor cap, and tried ethanol treatment with higher quality gas. With all this I had two small issues last week down at Norris Lake.
What I've found as the best prevention is to start my engine every 20~30 minutes or so, idle longer before planing out, idle longer after the initial stop, and running the blower more often. By doing this, my issues were just a simple stall, and I was able to re-start pretty easily. The previous years, i'd literally have to crank and crank and crank before I'd eventually get started again.
I probably haven't helped much, but can certainly give more details if needed.
BTW...did you get restarted when this happened?
