BluegrassBushcraft so one of the great features that both Optimus and Primus have incorporated into their stoves is a ‘flip stop’ feature. On the Primus, the pump is mounted at an angle. In the ‘on’ position the pump and pickup stick down into the fuel. When flipped to the ‘off’ position the pickup sticks into the air at the top of the tank. This runs the remaining fuel through the system, and bleeds the pressure out of the tank through the jet. There’s never residual fuel dripping off the burner this way. Also blowing air through the jet helps keep the jet clear too. Finally the upward angle of the pump plunger in the ‘on’ means that you don’t scrape your knuckles on the ground while pumping. It’s pretty clever.
