I had one of them on my old SR4..... Only had the carbs off once, and even admitting Iv'e had a couple of beers nothing jumps out my memory other than the slightly crazy "one bolt does all" to hold them & the air box onto the engine so you kind of ideally need to be a bit of a gymnastic octopus to reassemble it all......
When reassembling, remember when you set the idle mix do it with the boat afloat or deep enough in a bin to simulate that as fine tuning the idle mix on muffs will result in no start in the water due to the back pressure on the exhaust.
It's also possible to tweak slightly and make it a 30.... but you need a new cam for the mechanism. Investigate the centre carb and all will become clear!