W & B
Some time back the Basic Empty weight did not include unusable fuel and engine oil. The original page of the C150 Pilots Operating Manual most likely will reflect that. You should refer to the current weight and balance report which should be relatively recent. Unless it too is very old it most likely includes unusable fuel and engine oil within the basic weght but always check! If so, as already made clear, for further calculations oil and unusable fuel should be ignored.