There is no need to apologise for any spelling.
The screw indicated is the fuel mixture screw and NOT for setting the idle speed. It determines the mixture of fuel and air that comes out if the carbs. Idle speed is set by adjusting the bigger wheel screw position underneath the carbs towards the back.
To adjust the mixture each carb will need to be set seperately. If memory serves me well it should be between 1 3/4 and 2 1/4 turns out. Screw it down fully then back it out 1 3/4 turns. Do this on both carbs. I then use a colortune spark plug and start the engine. This lets you see the colour of the burning fuel. Adjust the screw until it is a nice blue colour. Repeat this on the other carb and the mixtures will be correct. After this task has been performed the carbs will need to be rebalanced.
If you do not have a colortune plug adjust the screw until you get the fastests smooth tickover. Back it off slightly and bring it back to smooth. Again repeat on the 2nd carb. This may require further tweaks to get it spot on.
