Originally Posted by maintenancenazi
Or could it be that these motors have a HUGE difference between new, and fully broken in?
This is most definitely the case, there's a significant & very noticeable change in power as the motor runs in.
Only catch is how long that takes seems to be wildly variable from engine to engine - but the consensus is at least a couple of hundred miles, particularly with the rich mixes/high quality oils.
S'long as your fuel/air mix is set properly w/a tan/brown electrode - I'd reco not bothering to tinker w/the carb trying to get any better performance until after the break in period - you'll drive yerself nuts