menzies
Guru
You know I was fighting what I thought was the same issues. I thought for sure it was some kind of ignition problem. New Cap/rotor/wires/plugs... same issue. I checked every wire against the firing order standard and reverse engines. Our engines have low hours so I did not think it was a carb issue. Boat would run fine just enough for me not to pull the carb. But I never could find any stand out problems with the ignition. The miss was always on the same side of the engine, pulled each plug and never really could pin point one cylinder that had the problem, seamed all of the off side were not running right. Pulled the carb off and it was very clean inside. Tore it all apart installed a new kit after a night in the dunk tank and a heavy blow down and clean.. Runs great now! I decided to also pull the other carb and do the same just to make sure there was no junk in it.
"Low hours" could mean the engines were sitting long enough that the fuel left in the carb "varnished", cluttering up the carb.