Hey there, thought this topic might interest a few people.
I’ve got a 4hp 4st 2005ish mercury and looking at upgrading the carb to the 6hp model as everything else is the same.
Emails to merc people have confirmed this. May then look at matching a better prop to it (pitch and diameter).
Anyways let me know if you’ve had any experience with this, otherwise
I’ll keep pursuing and post how I get on.