I have a 1993 Merc 8hp that I aquired (barely running) with a package deal. I replaced the top and bottom crank seals and cleaned the carb and it runs really nice now. What I can't figure out is what that the fast idle knob actually does. It seems to have no affact on anything when I turn it back and forth. The sticker is worn so i can't tell which way supposedly makes it idle higher. I studied the mechanism and it really doesn't look like it would do anything. Maybe something isn't hooked up or missing?? There is a plastic arm that has a rod attached to which goes up under the flywheel. Again, I see where it goes. I just fail to see any function here.