Hi ya all, been a while. I've got a question for the experts out there, why would my xr4 keep running if i wind the fuel screw all the way in? Shouldn't it die? What is this a sign of? Could this be a sign of a missing O-ring from in there? I have had the screw out and nothing has come out apart from the spring, the O-ring may be jammed up in the hole but with a casual look i can't see anything that looks like an O-ring. If it is missing should i replace it, would it cause this issue? Carb is the standard Mikuni btw. Tia.