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.

 

[DareDevilDave]

Next question, I have a mercury classic 40hp that runs good but doesn't seem to have a lot of power. My buddy is trying to sell me his mercury classic 50hp but I'd hate to swap them out and dont feel a difference. Pain in the ass to swap? Not worth it? I attached a pic of the boat I bought. Thanks