Hello Don, I had a 1998 Johnson 40HP motor with the VRO system, and still have the shop manual for it. The manual only goes up to the 70HP engines, but I imagine the VRO systems probably work the same. The VRO is vacumn pulse operated by a combination air motor, fuel pump and oil pump. Contrary to popular opinion it is a pretty fail safe system, the air motor that drives the fuel pump also drives the oil pump at the same time. That motor should have a low oil alert for the oil tank, and there is also a no oil alert in the VRO pump. The manual also has a step by step description of how to bypass the oil pump if you want to run mixed gas. If you need any more specific answers that my manual could be of help, let me know.