I would suggest finding a manual for your engine to help do this. It's not as simple as just plugging in some wires and the hose. The manual for my 1987 Johnson 50hp has 10 pages covering servicing and testing of just the VRO system.
The VRO was disabled on this 50hp when I bought it and my plan is to also reconnect and use it if it is still working. I will be using and following the manual step by step as I proceed.
Just for an idea of what there is to it. 1st step run mixed fuel until it is found that the pump is working. The oil hose needs to be primed and once primed do not disconnect it. 2 wires from the oil tank and then also a plug cable from the VRO pump to the engine need to be connected. Then comes all the testing which is involved, many steps. Which is why I suggest a manual.
