Boat motor question?

[DareDevilDave]

What is the purpose of this screw on my 1991 mercury classic 40hp???

 

[Retired-Guy]

Pobably idle speed adjustment.

 

[NDbowman]

I'm not a boat motor guy, but it looks like an idle speed adjustment screw to me also.

 

[tikkalover]

Is that lever mechanism for the throttle or for shifting from forward, neutral and reverse?

 

[jdfisherman]

Pretty sure that's the adjustable stop to set the neutral position for the shifter. The two adjusters below it set the forward and reverse stops.

 

[tdismydog]

Idle screw I have the same motor.