Yes, it can be done.
Yes, your Suzuki dealer will be able to help.
But expect it to be a bit expensive.
And it will depend on whether your 40 is new or older as to whether it can be done easily or with more difficulty and expense.
Depending on engine year, about $300-$400. You need a Suzuki engine intrface cable, an adapter cable to plug it into the engine, and a NMEA2000 starter kit ($70).
But it will get you a lot more than just fuel use. It gets you all engine related data including
RPM, alternator voltage, engine temperature, engine hours, trim (on engines with a trim sender) fuel flow rate, fuel used, seasonal fuel used, trip fuel used. Newer "A" series also get water speed.
If you want to understand more about this stuff, I wrote a pretty comprehensive article for members on the Suzuki outboard forum, here is a link if you want to read about it:
http://www.suzukioutboardforum.com/f...a2000-networks