with the cowling off, listen and visually check to see if anything happens when you push the key in.
may be those 2 devices on the carbs 1& 3 operate when pushing the key, but that is not the way the prime start works on my C40 2 stroke.
just because you can push the key switch in does not mean it does something, but you can verify easy enough
I had a 35 Evinrude that squirted fuel into the carb when I pushed the key switch, but it also had a lever I could push on the carb if the electric part did not work