I have loved the engine, but starting this year, it started using much more oil than normal. On a recent week long trip it became more obvious, I did not calculate exactly, but somewhere in the ratio of 25:1, which is way more than usual. I usually only go through about 1.5 -2 gallons of oil a year and almost used a whole gallon on a tank and a half of fuel (40 gallons). Also seeing black buildup on exhaust port and smelling exhaust at slow speeds which has never happened before. Any ideas? Dealer wants it dropped off for 1-2 weeks to look at it and do not want to be without boat for that long at this point if it is something I can fix myself. Thanks in advance for any help.