i just bought a 15hp 1986 evinrude out board, theres adjustment knob next to the choke, and i dontt know what it does, i haven't had it out on the water yet.  Anybody know what this is?

Im guessing the lean-rich knob.

Im guessing the lean-rich knob.

If the oil and fuel is mixed in the tank, how is the motor gonna take some out or add some oil to the PREMIX?  That is the idle adjustment.  It adjusts the RPMs at the lowest throttle settings.  That way, at different altitudes and temperatures, you can still idle as low as possible, without dieing.  

i thought it was something like that.

thanks

I used to have a similar 18 hp motor and never found that the knob made any diferance.

I used to have a similar 18 hp motor and never found that the knob made any diferance.

We ain't never bothered to use it.  In the winter it often stalls out at the lowest throttle.  Instead of adjusting the idle, just give it a teeny weeny bit more throttle.  Problem solved.