With the carb still sitting upside-down on the bench, measure the distance from the carb body gasket surface (WITHOUT the gasket in place) to the highest point on the black plastic floats (without putting any pressure on the floats). This measurement should be between 20mm and 22mm. If adjustment is necessary, gently bend the metal float bracket on each float to reach the right height. A simple tool can be made to measure the float height out of cardboard, simply cut L-shaped pieces that measure 20mm, 21mm, and 22mm from the top of the L to the top of the leg of the L:
After setting the float height, reinstall the float bowl gasket, float bowl, and carb body. Install the carb slide and top, and if necessary do the other carb. Don