Before you unhook the VRO, google "The myth of the VRO" it is an interesting read. I don't pull them off if they are working.
Having said that I have two oil injected motors right now on my boats. Neither one is using the injector, but I did not unhook them. I unhooked one yesterday on a 140 Evinrude that failed and was dumping oil into the system as a fail safe. Only reason I unhooked it is the difference in cost between a new VRO pump and the readymix pump, several hundred dollars.
The primer red handle goes paralell to the primer body in the run position. It will flood the heck out of your engine if it is in the wrong position.
After it sat for several years I would clean the carbs, change lower unit oil and impeller at least. Probably rebuild the fuel pump, which may be reason enough to change it from VRO, when you consider the cost of even the rebuild kit for the VRO pump. You can buy a 3 hose pump that goes right in where the VRO comes out and hooks to the existing hoses. Look for an OMC 3 hose fuel pump on Amazon. Make sure you get the hoses back on right, vacuum, fuel in, fuel out. Unplug the VRO and you are good to go. Mix some oil in the gas and pump it through the system to get mixed fuel to the carb. Unhook and plug or remove the oil line if you unhook the VRO.
I have taken to unhooking a fuel line and idling my motors until they just hiccup in the Fall to get as much fuel out of them as possible. I then empty any fuel in the tanks into cans and run it through my 4 wheeler or pickup to get rid of it. The 2 stroke oil in the fuel hurts nothing in 4 stroke motors. First trip out in the spring gets 100% fresh fuel.