As I wrote earlier all the idle speed screw does is stop the slide from going right down, so if the cable makes the slide open and rev up, the stop screw must do the same.

 

Here is a video of it running Got any ideas why it sounds so bad?

 

Sorry, no. It sounds oddly like a two stroke at idle. I guess the idle mixture screw could need tweaking, but I avoid them as a rule, usually awkward to get at, and all the workshop manuals say, don't touch.

 

Thats what I was thinking, it did sound like a 2 stroke. And I have messed with the idle mixture screw a small bit but it didn't seem to make a difference. I will mess with it a lot more and see what happens. It already aint runnin right so what harm could it do. Also I heard that it might be a bad spark plug.