IT sure can be! The biggest MYTH you have to overcome with the power valve is that they can influence idle. That's just so untrue it's pathetic and you simply cannot tell people that who don't believe it. You can actually remove the power valve and throw it on the ground, reassemble the carburetor and it will start and idle fine. Since the power valve is not on the idle circuit, it has zero effect there. Now, the metering rod carburetors are a different story. Even though the metering rods are on the power circuit, they do have a small effect on the idle mixture.