I have a Robart Super pumper. I installed it on a SuperTiger bluehead .40 That engine had a .60 size carb on it from new. The engine was well broke in with many flights when I installed the pump. It was kinda hard to tune & ran a little rich on low end. When you got to 1/2 or full throttle...WOW... did it ever scream. It must have jumped 2k better on top RPM. I still have the pump....used silicone spray to keep it good. May try it again some day. Got all the papers with it too. Capt,n