Engine starts and idles with an occasional miss but starts to stumble at 2000 rpm and up. <br />Reachs a maximum rpm of only 3900 and around 20 mph on a 1650 Lund Explorer. Number 2 plug is the only one that shows black as if it were too rich. Disassembled and cleaned no. 2 carb. Swapped coil with no differnce, changed plugs and new fuel filter. Engine has never gotten close to 5500 rpm even with switching props. Have the recommended prop on at this time. Am at 3500 ft elevation but have run at all different elevations with out much change in performance. Mercury perforance tests on this engine with similar boats is 32 to 35 mph. I think something has been wrong since new but this severe problem just developed this last time out. Please help.
