Ok, I feel really silly for asking this but.... I just purchased the LM2135SP. This is my first battery powered mower. I have taken it out of the box, assembled it, charged the battery, followed start up instructions and the mower will propel but it is not cutting. It appears the blades are not turning. Does something need to happen to the blades before the first use? Am I doing something wrong? I followed the instructions in the manual for starting the mower with blades on.