Re: MPG to expect on a 98 200 HP carbuerated outboard on a 22' boat
I don't have a "total or extensive" collection of test numbers but my source is boattest.com
Alot of the mfgs and dealers give these guys a boat for the day to do "real world testing" with the agreement that they will post their actual findings regardless of whether they support or call into question the claims of the mfg.
Because it's a voluntary thing so you don't always get every combination of boats/motors, in fact there is a very notable lack of data on Evinrude ETEC's.
But Merc, Yami and Honda are active participants on the outboard side with Volvo and Mercruiser in the I/O flavour - those combined with the many boat mfgs that like the free advertisement for their products means that even if your exact combo hasn't been tested, you can usually find a "similar hull" that should give you a reasonable approximation of what you may see on your own rig.
Since they mostly test "new" rigs, recent tests are almost exclusively DFI 2 strokes and 4 stroke outboards, but since they also occasionally test (resale) models, you do trip over the odd test for carburated 2 strokes.
Anyhow, check out the site (boattest.com), lot's of good info, the drop downs for the test data can be found at the upper left of their main page...