[Mark Murray]

I purchased a 1984 70 hp Evinrude and the single lever controls have a little knob on the back/stren end of the control box that I can turn left or right about 6 rotations without noticing anything happening? Also, there is a little button/switch on the face of the control box that I don't know what it's for either.

[rockyrude]

The knob that you are turning is a friction adjust so the control doesn't vibrate back while underway. The button should control your choke, you hold it in to choke the motor when starting.