Adjusting idle speed and low speed air/fuel mixture

My Selva Madeira 40 XS is running a little rough and I wanted to adjust idle speed and low speed air/fuel mixture. Unfortunately the user manual does not even mention these topics and I have not been able to acquire the service manual.

With a little help from Italian guys from Gommonauti.it I collected courage to adjust screws next to the carburetors.

One needs to adjust screws 2 and/or 3 to adjust idle speed. Of course your motor needs to be warm before messing with these screws. I adjusted the idle speed to 1000-1200 rpms. You need turn both screws same amount. Update Sep 2018: you need to turn only one screw, it will adjust both carburetors the same amount as they are synchronized.

In order to adjust low speed fuel/air mixture you need to adjust screws 4 and 5.
The range is 2-2 1/2 rounds. I first closed both screws and noticed that they are not perfectly aligned so you need to be careful when rotation those. I used marker pen to color half of the screw, it helps a little when you are turning the screw.
You should first adjust fuel/air mixture and after that bring the idle speed to suitable level using idle speed screws. I don't know what is the proper idle speed range for this motor but about 1000 rpms is the most common value.

Dangar Marine has published a great video about carburetor tuning, I recommend to watch that before touching anything =)