Yes, Hi and Low needles, it is a bolt on, it's got a primer though, so you have to block that off, that's it, and then rig some type of throttle. The throttle arm on the WYB carb that came on the GX-25 had a plastic throttle arm, it was pretty flimsy, the WYK 61 looked very similar, but was actually metal inside, with a plastic coating, so It was easy to drill and tap for a bolt on ball link.