This breakdown should show the separate floats which will contact the float arm. If the float arm is level to the carb body gasket surface, then the floats should be able to function properly when installed correctly. Fuel level will be close to correct, should be in Range.
A "Hiss" when opening the bowl gasket, could be blocked bowl vent. The nipple on the right side of the carb body it the vent. It should of course be clear, no obstruction.