You want to measure the height just as the float touches the needle. The easiest way to do this is to hold the carb at a 45-degree angle. Then watch the small metal tab on the float as you move the float up toward the body. Just as the float touches, that’s your level. If you hold it straight up and down, you will have an incorrect height. The float will impart too much pressure on the small spring under the pin in the needle. That is the biggest mistake people make when measuring float height. If you need to adjust the height, up or down, just slightly bend the tab that contacts the need in the correct direction.