Help with Controls on 1989 4hp J4RCEC

[Slimbob]

Hello,
I don't have an operators manual for my 1989 Johnson 4hp engine. I'm wondering what the second knob does. There is a choke knob and another knob that looks just like it. This is the one I'm not sure of.

Any help available on this?

Thanks,
Slimbob

[boats.net]

The second one should adjust the slow speed circuit (Idle).

[Slimbob]

Thanks for the input.

Slimbob