Hey guys, I'm rebuilding the carbs on my 1984 90 hp Johnson (J90TLCRD) and I noticed that they only have on set of jet screws, not high speed and low speed jet screws. Was this something that changed with the VRO system? Also, the base cover is plastic and the carbs look new. I've watched a video on carb rebuilds and I have an old set of carbs from an '81 Evinrude and noticed two sets of jet screws and that the base was metal. Just wondering if they're aftermarket or what. If you need more info please don't hesitate to ask. Thanks!