I have an 18.5 ft Cajun center console that had a 95 Force 120 on on it that would run 38mph at about 5300 rpms until it broke a headbolt and cracked the block. I bought a 91 Force 150 5-cyl that had just been rebuilt by a local boat shop. After a twelve hour breakin with double oil I put in new plugs and went to the lake. The 150 doesn't have the power of the 120. It idles smooth but it takes longer to get on plane, runs rough between 2000 and 3000 rpms and the top end is only 4500 rpm with the boat trimmed level with only me in the boat. The 120 would still turn 5300 with a 1000lb load. The rough running sounded like carburetion. They look clean inside but I notice the main jets on the top and bottom carbs have .094 main jets and the center carb has a .078, is this normal? Does the center carb only feed one cylinder? The shop gave me a 60 day verbal warranty and after taking it back several time until the 60 days was up I was told all the 150's ran this way, even when new and the different gear ratios of the lower units requires that run a prop with less pitch than the SS 17 that came off my 120. I know now he's blowing smoke. Any ideas? 1jmoxy@msn.com 