ORIGINAL: Wayne22
Actually, the best place for the shutoff is before the pump... Should you have a runaway pump (ecu failure) and it runs at full pressure, instant shutoff at the valve could burst a line (has happened!). Much safer to kill the supply than the pressure
The location of the fuel shut off valve is only as good as your ability to reach it when needed. Once the jet is buttoned up and on the runway, or in the air, it is only along for the ride (unless you have a servo to close it).
If it is a Festo type ball valve, it should always be on the pressure side. If it has barbed fittings (and is safety wired, it can go on either side of the pump.
Here in Australia we must have a servo controlled shut off valve. We must demonstrate this to the inspector before we get the "Permit to Fly" signed.
You can have the model "buttoned Up' and still shut off the valve. I have mine between the pump and the engine, the servo will turn the Festo Tap OFF, but you need to manualy turn it ON. I have the servo wheel facing the tap with a 4.40 screw that pushes the taplever.
Works for me