Both carbs HAVE to be synced or you will never get them to work right. It take patience and a bit of trial and error to get right. This Guide will help you and save me from typing it all out. Running rich is bad and your buddy should feel bad for that mistaken advise. Having one carb rich and another lean is worse. A broadband a/f gauge is a very good tool, but you should be able to get close without one. YouTube has vids to help out as well. HTH, Steve