Good advice here on taking pictures before breaking apart, that is a very smart idea. My father and I just rebuilt the carbs in his pontoon boat a few weeks ago. From what I noticed, what's going on with the ethanol gas is that it's eating the seals inside the carbs. Those eaten parts then get lodged in the holes on the carb, which causes problems. The best solution is to pay the higher price and run non-ethanol fuel (recreational fuel). One big word of advice I can give you when cleaning the carbs is to definitely invest in a carb cleaner dip (father used berryman dip (walmart)), not dipping your carbs in this solution and only using a carb jet sprayer, such as gum-out, is a big mistake. The process we used was to first spray the carb out with gum-out(or similar product) then dip the carb in a cleaning solution for about an hour, and then spray the carb again with gum-out spray. The boat has been running the proper RPM ever since and sounds great! Good luck, let us know how it turns out.