I have a 25 hp Mercury. Probably about 15 years old or so. Lately it doesn't seem to want to run at WOT for more than about 30 seconds unless I constantly pump up the fuel ball a little bit. It will lose rpms and just die unless I pump the ball. It is almost like it isn't getting gas into the carb fast enough or something (or maybe it is sucking air into the fuel?). It has a new fuel hose on it. I took apart the tank and it appears to be in good shape. The fuel filter is very clean and I can't seem to find any cracked hoses or anything that looks odd. The gas tank is also vented so that isn't the problem. The motor runs great at lower and mid speeds. Some people have told me it is the tank (which is about 15 years old), but it doesn't look like much can fail with the tank. I just wondered if anyone had any suggestions or if this has happened to them before. The ball does not get "sucked in" as I am running it by the way.
