I have a question. Under my key switch there is a knob that you can turn. I was told that it is to adjust the air/fuel mixture. Is this true and if so does anyone have any tips on how to adjust it? thinks 

Should be marked in some way - 'Lean' and 'Rich' being the old notations on the 23' Cruiser my dad had when I was a teen and I took out fishing occasionally. Cold starts, put it more towards Rich. Once it warms up, turn towards Lean until the sound evens out. Through the day, you shouldn't have to adjust it again as the motor will still be warm even after an hour or so parked or slow-moving with the TM.

thank you very much

A little more info, motor, boat etc.  maybe a picture.  

I seriously doubt it's a mixture adjustment, don't know of any modern motor that would have that.

My guess would be the controls for an old Lowrance in consoled flasher, but without some info, it could be most anything.

 

Its on a 1986 ranger 320v. 115 evinrude. it is built in from the factory. Its just below the shifter where the key goes in at. all the old timers i have talked to said it was for fuel mixture, I was just wanting to know. my boat does run a little rough after it warms up. and they ask if i adjust that knob. i was wanted to make sure what it was before I fooled with it. thanks

 

early pre 70's 2 cylinder OB's used a carburator adjustment knob 1/4 turn lean or rich, those engines you pull started no on/off switch.

Tom

6 minutes ago, WRB said:

 

early pre 70's 2 cylinder OB's used a carburator adjustment knob 1/4 turn lean or rich, those engines you pull started no on/off switch.

Tom

So is my knob just there and not hooked up? My motor is a 1986 evinrude that has a starter is not a pull start. I looked at a on line owners manual and it doesn't talk about it 

it is a v4 two stroke eng

14 minutes ago, Daniel Abram said:

So is my knob just there and not hooked up? My motor is a 1986 evinrude that has a starter is not a pull start. I looked at a on line owners manual and it doesn't talk about it 

it is a v4 two stroke eng

Way2Slow is an expert on OMC OB's and will get back to you.

The old OB's lean/rich was a slight mechanical adjustment to optimize fuel mixture on 1 carburator, your engine has multiple carbs and a knob would be electrical not mechanical if located away from the engine.

Tom

1 minute ago, WRB said:

Way2Slow is an expert on OMC OB's and will get back to you.

The old OB's lean/rich was a slight mechanical adjustment to optimize fuel mixture on 1 carburator, your engine has multiple carbs and a knob would be electrical not mechanical if located away from the engine.

Tom

ok thanks

 

just found a youtube video on it, it controls tension on the shifter