A couple of comments...

Many of the suggestions being made in this thread apply to all boats and all engines, not just the 240EFI. The idle RPM's thing is specific to the 240EFI, but things like normal maintenance are part of owning a watercraft. Just wanted to make certain the 240EFI wasn't coming off sounding like a piece of junk. It's not - it's a great engine.

I have the 240EFI service manual and I'd swear there was some ability to adjust the idle speed within a limited range without affecting the ECU. I'll check and report back.

As far as engine hours, the 2002+ models were Mercury SmartCraft compatible so that may be why they store the hours and older units do not.

Finally, there is a very highly recommended aftermarket alternator available for the 240EFI. It kicks the current output up by 50 amps and (I'm told) is a breeze to install on a stock 240EFI. You leave the existing stator and regulators in place. I've seen pictures and it's pretty impressive. Cost is around $700 I believe. If anyone is interested I'll post the website. This kit is often used by race boat owners who have Mercury powerplants based on the same 2.5L powerhead as the 240EFI SportJet.