2001 merc. 225 efi stalling above 4000rpm

[futonman]

I have aproblem that has gotten worst with time. When I get above 4000 rpm the motor will just shut off. It started doing this about 3 months ago, maybe once a day, til now it only will get above 4000 rpm for about 20 seconds. I have replaced the fuel filters, primer bulb, fuel lines, presure regulator,numerous o-rings and gaskets, and rebuilt the mechanical fuel pump.The pressure is at 34psi.I've also checked the tank pick-up and vent. I also put in a new set of spark plugs, even though the old ones looked fine.Could this be something besides a fuel problem? And if so what should I be looking at? Thanks Steve

 

[futonman]

Re: 2001 merc. 225 efi stalling above 4000rpm

Just posting this to help anyone with the same problem. I had replaced all the fuel lines, except the green "mercury marine" Line that went down the wire harness tube from the transom to the motor, becacuse it was almost imposible to get out. Well I ran the boat on a 6 gallon spare tank and problem gone.Ended up unhooking both ends of that green mercury fuel line to blow air through it ,and it was pluged solid. I don't even know how it was able to pull any fuel through that line. Seems like Mercury fuel lines have an inner core that breaks down over time. Replaced it with a new fuel line and just took it for a test run it ran great all the way up to 5800 rpm. So if you have any Green Mercury fuel lines, swap them out. Steve