I have better luck setting the float level with the engine stopped and car on level surface. BUT if you find that you need to change the level I would advise you to remove the lever from the cover as some times just bending in place will break one of the bosses for the lever pins . Or you can support the lever with needle nose pliers. Then you can measure and bend the amount needed. I start with the intermediate needle opened to 27 or 28 clicks. I have not read the instructions that come with the kits but the adjusting instructions from some C Yapp articles state that the idle mixture controls the fuel but they actually control the amount of air. The more you open the idle mixture needle the leaner the idle mixture will be.