pilot screw/air screw?

[spete]

I have a yamaha 115 and the manual/carb detail shows a pilot screw and an air screw. Can someone explain the function of each of these and why the book only gives an adjustment range for the pilot screw? Do I need to adjust the Air screw also? Looks like the pilot screw was adjusted out to the high end of the range - would that cause a rich idle condition?<br /><br />Thanks for your responses

 

[spete]

Re: pilot screw/air screw?

Also wondering if both carbs/pilot screws should be adjusted exactly the same or if you should look at each pair of cylinders/plugs separtely and see if one needs to be adjusted differently than the other?