Hopefully someone my be able to help!!! I am at my whits end with this one. I purchased the engine under the impression that it only needed a switch box, although it had been sitting for two years. I have replaced the switch box, rebuilt the carbs, replaced the fuel pump, and checked the compression. All have checked out Ok. I have even taken it to my dealer to check and set the timing. What esle could it possibly be, it has spark and gas just no power. i will get on plane and run but no power. It is on a 15' Whaler so it should be sick fast, it is only doing 35mph. Sorry for the long post hope someone can help.