Don’t. Cold water can cause structural integrity to be compromised as well as cracks or serious damage to the engine and generator parts when it is sprayed upon hot metal. Generally speaking, water is not the friend of a generator. Spraying water into generator components can damage connections and allow moisture to enter the fuel or fuel lines. Water can cause rust, which can weaken parts. Also, While the generator is running, any leftover water inside or on it could electrocute someone.