Fuel consumption issues on DF300

[Bbradford]

Have a pair of DF 300's. Just had boat a in for 400 hour service. Got new plugs, fuel filters, etc. now, Starboard engine is burning about 20% more fuel than port and will not turn up over 5300 RPM where before I brought it in, it was turning up to 5800-5850. Felt spark plugs, all were warm so believe all are firing. Engine runs fine otherwise but boat is very lathargic like both engines are not performing correctly. Any ideas?

[boats.net]

It needs to checked with computer diagnostic and they need to recheck that they didn't leave a sensor unplugged.