My ECO pump has the 9mm plunger so I'm good there. The worst part is you have to remove the MAX fuel screw to get the LDA back on. Also the idle screw is in the way of one of the cap screws, i've removed it once with a ball allen wrench but almost stripped it. The advance linkage I will hook up so I can have a high idle in case I have a PTO (hehe jk).Giles this is the pump some guy sent you a few weeks ago to test, he lives near you.Does anyone know what the MPG difference is between ECO and not ECO?