Can't remember the reason P.O. melted the piston, think it was a plugged up carb from improper storage and/or bad gas, he had to bore out that cylinder and replace piston with over sized one.
Guy that rebuilt and sold me the Johnson told me he would hook up the VRO, and it did have the "type 3" or newest version of fuel pump, but he would not warranty motor if I did ...
I didn't have room under splash well with the two 6 gal. gas tanks anyhow ... so never tried it.
I did do some reading into VRO also, some go years without problems and others are not so lucky.
Friend of mine is second owner of a fishing boat, about a late 80's model with a 90HP Johnson, he has never done a thing to his VRO system except tape up the cracked rubber lines ... OMG !
Boat get used all summer for fishing and into the fall for hunting ...
I believe the thermostat stays open and motor runs to cold, won't idle or run at low speeds.
He said there are two versions, one is stainless steel and should last longer ... Only lasted one season for me ...