I just acquired a kind of basket case ch150 and I want to build a skelly out of it. I am in the process of rebuilding the carburetor and this model has an air cut-off valve. I didnt get the valve while it was put together so I am not sure if there are internals that I am missing. Is anyone familiar with that? The parts view only shows the entire valve and the service manual doesnt mention anything about whats inside the valve body.