Hi, This subject was posted by "tjtraver" on 2002-07-03. I was wondering Todd, if you had any successful outcomes, because my motor is doing the exactly the same thing! I have pulled the carby apart and everything looks 'in order', also all the fuel lines are clear. After about 20 minutes flat stick, she dies. Any help would be much appreciated, as before this problem the motor has never let me down. "I have a 4 or 5 year old yahama 25 hp 4 cycle engine that starts and runs fine for about 30 minutes ... then the engine quits running and has fuel running out the overflow from the top of the carb... Anyone have ideas what's going on here ? Is it somehow fuel presure related ? Any insights into this problem appreciated ... Thanks, Todd Traver"
Had the same thing.Turned out to be a float needle valve problem.Disasemble the carbs carefully and check and clean all the float parts in each of the carbs. I had 4 carbs on my 50 4 stroke Yammy. These guys have a habit of gumming up for no apparent reason.