When greasing an electric motor, you should add grease until it comes out of the plug.

When greasing an electric motor, it's essential to avoid over-greasing, which can lead to various issues including excess pressure that could damage seals and lead to a buildup of heat. The correct practice is to only add grease until it begins to show at the grease fitting or until it starts to ooze out slightly—this indicates that sufficient grease has been added to the bearing without overfilling it. Overfilling can cause grease to escape through seals, leading to contamination, as well as increase friction and heat, which can shorten motor lifespan. Thus, stating that one should always add grease until it comes out of the plug does not align with proper lubrication practices.