@StefanD For your information, these kerosene stoves operate with max. 0.4 or 0.5 bar usually. This is much less than the pressure in the pressure-lamps (Petromax), which have much stronger founts. If the pump is working well, you should get operational pressure with 20 to 30 pump strokes, depending from the filling level. I use a pressure gauge sometimes for tests. Radler
70–80 pump strokes? My Primus 96 needs around 10 pump strokes to start up properly. Perhaps there's something wrong with the pump? Or is the NRV spring set too tight?