just purchased boat 2 days ago. Equipped with 2002 mercury 90 hp 2 cycle. The outboard appears to be in very good condition, not a scratch anywhere. My problem is the engine doesn't seem to idle smoothly and has a definite miss at higher rpm. The boat has not been used or ran for last 9 months. I drained old gas and replaced still no change.Would a carb cleaning/rebuild be in order? If so what would be a fair price to pay for this service? Thanks