I recently purchased a 14' fiberglass boat with a 25hp Evinrude outboard. I am having some problems with power loss at full throttle. Sometimes the engine works perfectly, but other times it only runs at 25% speed. It usually runs this way for a while and sometimes gags and goes to full speed. Does anyone have any suggestions for me? I just replaced the spark plugs, but the problem persisted. I am starting to think that there may be a problem with the carburetor. How can I obtain a breakdown print of the carburetor so I can clean it? Thanks in advance for any help.