A method and apparatus is provided for starting and stopping a high pressure spray washer having a combustion engine driving a pump to provide high pressure fluid to a spray gun activated by a trigger. Pulling the trigger causes water to flow through the nozzle and pump and a sensor by the pump sends a flow start signal to a control module that activates an electric starter when an engine switch is turned on, thus starting the engine when it wasn't running. When the trigger is released flow to the pump stops and the sensor sends a flow stop signal to the control module. If a predetermined time passes before the sensor detects fluid flow to the pump as occurs when the trigger is pulled, then the engine is shut off. The time can be varied to adjust the time between releasing the trigger and shutting off the engine.