I have a 40 hp 3 cylinder Mercury outboard and it bogs down when I get to half throttle... I've narrowed the problem down to something to do with the bottom carb because when I would spray sea foam into it, it restored full power. What do you think?
Check stator...how are you spraying sea foam in running it under a load at half throttle....reving an engine means nothing...with what you are saying idle jet clogged....take all the carbs apart and clean and replace needle and seat...Ethanol does these in unlike our old gas of yesterday....