I am not sure it matters but I highlighted that plug because the original discussion was if the valve had a main RV, it doesn't and there is a plug in its place. This plug 'shuts off' the connection between Pump and Tank which the RV would be using. So the plug just is a blanking plug for the RV port when you do not want an RV - the customer (Kubota) specified the valve without the RV so it is likely there is one closer to the pump somewhere but I don't know where because I am not familiar with the machine circuit.
In this case, this plug does not make it close center or adjust the connection between Power Beyond/Pump/Tank as some "shut off" plugs do.
In this case, this plug does not make it close center or adjust the connection between Power Beyond/Pump/Tank as some "shut off" plugs do.
