Board Thread:Questions and Answers/@comment-5887175-20121218174115/@comment-5886838-20121219012940

80.192.207.217 wrote: Redstone engines only start pumping when they're orange/red (That's what I've noticed, but it may not be 100% accurate) Redstone engines pump when powered, however when they are yellow/orange/red they pump much faster, or in other words they pump at a higher rate slash efficency. When a redstone engine pumps at full power they emit one MJ which is the BuildCraft power.