A 12V Stop Solenoid is an electromechanical device used to control the fuel supply to a diesel engine. It is typically used in generator sets, heavy machinery, and other diesel-powered equipment. The stop solenoid works by interrupting the fuel supply to the engine when power is removed from the solenoid. 12V Stop Solenoid is controlled by a 12V DC electrical signal that is supplied by the engine control system. When the electrical signal is present, the solenoid allows fuel to flow to the engine, allowing it to run.