I have a 1978 Evinrude 35 hp on the back of my 13ft Whaler which has been giving me problems since I first bought it. When I bought the boat the engine had not been run in about two years so I replaced the plugs and lower unit oil. It ran fine the first few times I took it out and then it started running rough because the gasket that goes around the mixture needle on the carb had fallen apart. So I made a temporary fix that lasted the rest of the season and worked. In the winter I rebuilt the carb. The first time I took it out after I rebuilt the carb it ran fine, but the next time another problem occurred. The engine would run perfectly fine while at idle and at lower rpms, but as soon as I would bring the throttle up to put it on a plane it would start to run rough. It would start increasing in rpm like it should but then bog down and it would do this repeatedly in short bursts so it would never get on a plane. If I pulled the choke out half way though, the engine would get up onto a plane and run almost how it should except that it would not get to its maximum power at full throttle but really close. So I figured that the whole problem was due to lack of fuel and thought that the fuel pump had maybe gone bad. I then rebuilt the fuel pump and thought that would solve the problem but it didn't. The only thing that I can think of is that the carb rebuild kit came with a new float and float stop which I replaced and that maybe the float is not set right, although I adjusted it according to the instructions and old float setup. I also put a fuel filter on my fuel line which is new but I don't think that is causing the problem even though I know that these engines can be sensitive to air leaks in their fuel lines. If anyone can help me solve this problem that would be great. Thanks, Jeff. 
