Re: 1985 Johnson vro 140
Which concern, the power pack or the sticky controls? If you're mechanically inclined there's no reason why you couldn't change out a powerpack or a coil. Do you have a Service Manual? If not, order one and you'll be glad you did. Usually you can find the original factory version on Evilbay.
If this is a new-to-you motor, you're better off running the full gamut of diagnostic checks on it; compression/spark/fuel. If the motor's been even marginally ignored you can usually safely assume that cleaning the carbs, replacing old fuel lines, dropping the lower unit to change out the impeller, etc. would benefit you in both the present and long term. As for the VRO, if it's working I don't see why you'd want to disconnect it. Yes, they're no different than any component of your motor and can break, but you can also blow a headgasket, but normally don't change it "just because". Verify your warning alarms are all working, and should something ever happen, keep some 2cycle oil on hand and then you can bypass the system. For now, it's much simpler to just "pump gas" than to pre-mix.