I have a 1976 85H.P. merc and it idles ruff, when I spray 2+2 carb cleaner into the top carb the motor races up in RPM, but with the bottom carb it does nothing, I have done a spark test on all 4 cylinders and I have a lighting blue spark on all 4 cylinders, and 150 PSI on all 4 cylinders also...