The amount of fuel that flows to the engine is controlled by a fuel-calibration cam (arrow) located under a cover toward the rear of the pump (shown here with the cover already off). This is perhaps the trickiest part of the installation, so it's important to follow the instructions exactly, including using scribe lines to mark the position of the cover so it can be reinstalled in exactly the same spot. Once the appropriate brackets and lines are out of the way, you'll notice the factory-installed tamperproof screw, which has no head, in the upper lefthand corner. Use a chisel to make a slot in the screw suitable for a flatblade screwdriver. All of the cam-cover screws will be extremely tight, so investing in an inexpensive impact screwdriver may be helpful.