Have Boat Questions? Ask a Boat Repair Expert.
there is no way to check crankcase pressure. We usually spray carb cleaner, WD40 or some other fluid and spray around the crankcase half, carbs, intakes etc. If the rpm changes there is a leak.
Have you checked the reeds? Any signs of water? Were the idle tubes removed from the carbs and cleaned? New carb gaskets?
How are you determining #2 is dead at idle?
Have you done a spark test or run with a timing light on each cylinder?
Depending on the rpm pulling a spark plug wire may not tell you anything. What is your in and out of gear rpm?
Have you done a leak down test?