3ltr engine, Max revs 3000

[High Flyer]

Hi Guys
All of a sudden our Maxum18 (3ltr) engine has suddenly developed a reluctance to rev past 3000, we have never had any trouble with it in the past reaching to its maximum WOT range - any suggestions appreciated as to the cause
Regards: John

[mmwjr]

Has the boat been kept in the water? If so check for marine growth on the bottom and drive. If not when was it last tuned up including replacing the fuel filter?

[High Flyer]

Hi - No growth, filter and tune up, OK