As you can probably tell by the title I don't do technical, but I do need to adjust the idle speed on my 328 as it is running way to fast (1,500 rpm). I have located the idle adjusting screw by looking in the handbook, see first photo attached. Now the question is, how do you turn it? The manual doesn't tell me that! Secondly, somebody else I spoke to said to adjust the brass bolt under "the elephants trunk", as this will also adjust the idle speed. This bolt can be seen in the second photo, but the manual says this is the By-pass screw. What is the purpose of this bolt, and should I leave it alone? Thanks in advance.