Jets, metering rods and power piston springs do wear out, and when the jets get "egged" out some and rods worn down higher fuel consumption is the result.
I wouldn't be in a bug hurry to recalibrate to smaller jets/rods, and for sure "rod" out the idle tubes because they get "varnished" up, plugged up and can negatively effect fuel consumption.
Marine set-ups are far worse than automotive because of the "wet" environment, stale fuel, drying up cycles, and long periods on not using them.
When you get time give me a call at the shop, I'll spec out some new tuning parts and a new top gasket for the install....tks.....Cliff