This engine came with a Sniffle Valve so I installed it. Apparently this valve lets access fuel in the integrator drain out after engine shut down. This is suppose to help hot starts next time. People report that a little fuel/oil comes out onto the floor once in awhile, but that's not a problem. I think this also helps prevent fire from back fires to. I don't know. You can google sniffle valvues on fuel injected engines. Anyway it is installed per drawing.