Ay ay sir!
buut as far as I remember when I When I adjust the screw to where I need it as far as idle, it won’t allow the choke plate to move
YES! it should not move. The choke cam is not really a fast idle cam, it is not eccentric, i.e it has no camminess to it, it is perfectly round. It will not change the throttle plate position no matter what the choke position is. What it IS for, is when you have a warm motor, the idle stop screw holds the choke open, so the warm motor does not flood. Therefore, this is partly the reason why you pump the throttle when starting a cold motor, it releases the choke and lets it close.
Turn idle speed screw in until it just contacts idle cam, then turn screw in an additional two turns."
I will do that on the bench, do I have to "open" the choke or do it on the closed?
from what I just said, this means that it does not matter, choke open or closed. Don't adjust that screw on the bench, tweak it with the motor running in the boat for target idle rpms, then adjust the cable to give you a little "preload" so the screw is always putting a little bit of pressure on the choke cam, and so the engine always returns to idle fully. Two turns should give you a good starting point, but if it does not start, give it half a turn more and try again. Adjust the screw till you get 650-750 rpm idle, in gear. If your motor idles too fast, but when you unscrew the idle stop screw it stalls, play a little with the idle mixture screw at the base of the carb. What I like to do is with the engine running, turn it one way until the engine begins to stumble. Then turn the other way until it stumbles (generally about half a turn). Halfway between these is the happy point. unscrew the idle stop screw a little again, and repeat the mixture adjustment again, until you get down to your target idle rpms.