Before a starter is removed from an engine, it is important to:

When working on a vehicle's electrical system, particularly concerning the starter, it is crucial to follow proper safety protocols to prevent any electrical shorts or accidental shocks. Disconnecting the negative lead from the battery first is the best practice because it helps to ensure that the vehicle's electrical system is de-energized effectively.

By removing the negative terminal, you reduce the risk of a short circuit occurring; if any tools accidentally touch a grounded part of the vehicle while you're working on the positive side, it won't create a path for electrical current to flow through. This can prevent damage to the vehicle's electrical components and ensure that you are working safely.

While disconnecting the positive lead is also an option for disabling the battery, it carries a higher risk of causing a short circuit if tools accidentally make contact with the vehicle's metal surfaces. Therefore, starting with the negative lead is the safer and more conventional approach in automotive practice.