I've got a 97 75hp Merc on a 97 20ft pontoon. When running between idle and 2000rpm it runs rough. Sometimes shakes the boat. Once we are out of the channel she runs pretty smooth. we do about 20mph at 4500rpm. I bought this boat this spring and the dealer said the cylinders were all good, within 5 lbs of each other. The boat starts and runs, it just runs rough. Thanks
