Extended test at Wide Open Throttle checking temperature limitations on the Gaokin Four Stroke Microlight Engine; climb rate around 670 feet per minute at 10k feet, oil reached normal operating temperature without a separate oil radiator. Pressure 1025 millibars, ambient around 16 C

Trial and error:-
Fortunately not costly mistake but could have been, for anyone following the fuel injected motor's progress

Main pump on any injection setup typically runs at 3 bar or 42psi, it keeps up that pressure on the output via a filter, and the injectors use that to squirt fuel on demand. My filter has a built-in sprung valve and sends excess back to the tank, so it's being circulated and filtered constantly

Where some go wrong is to put a 10 micron filter on the input side, (or as I did) undersize the pipework the pump has to suck through. This causes the fuel to flash evaporate on the suck side, especially in warm weather, and the resulting cavitation destroys the pump. Input filtration needs to be 75-150 micron.

Once the pump started making high pitched noises this hot weather, started digging up similar stories, the poor thing was pulling through the standard 6mm outlet with a 4mm bore moulded in tube, the pump itself has a 12mm inlet barb, I've upped the outlet to 8mm with a 6mm bore and power is restored, it had been dropping off unnoticed as the unit has so much excess grunt. Ordered a 10mm set and will swap when that turns up. For the maths buffs, the pump shifts 130 litres per hour, and a 4mm bore tube means it hauls 2.7m+ per second through it, 6mm bore drops that to 1.27m/sec, feasible but for long pump life and avoidance of problems in hot weather, needs to be bigger still