Final answer:
It is important to disconnect the negative lead first from the battery before removing a starter motor in order to prevent electrical shorts and reduce the risk of sparking.
Step-by-step explanation:
Before a starter is removed from an engine, it is important to disconnect the negative lead first from the battery. This practice helps prevent electrical shorts and the risk of sparking, which could potentially cause harm to both the person working on the vehicle and the vehicle's electrical systems. It is essential because the chassis of most vehicles is connected to the negative terminal of the battery, so disconnecting the negative lead first helps to ensure that most of the vehicle is not energized during the removal process. Electrons actually flow from the negative terminal of the battery to the positive terminal, which can be counterintuitive since the current flow is considered from positive to negative.