How do you measure the hub diameter? The hub is measuring 4 3/4" od. I think it's a 1985 150 hp BlackMax XR2 ??? S/N A166483 or is this a 86? What is the WOT rpm range on these. And the gears, one has 14 teeth and the other has 28 teeth. Does this mean it's 2:1 gear ratio?
Thanks a bunch
