Weird Vibration on Catalina Universal Engine at 2000rpm

[AMICUS]

I have a 1981 Catalina 38'. I have owned this boat and sailed it more years than I can count. I love going to Catalina Island on nice summer days but I have a problem. My boat is located in San Diego, and usually the direction to Catalina for me is up wind. That makes for a 13 hour boat ride to get there. The main problem is that when I rev the engine to around 2000 rpm, the whole boat starts to vibrate and make a really load noise. A lot of people have told me this is probably a cavitation issue, however I just don't believe that. This boat has made that racket from day one, and I have a hard time believing that a brand new boat would rattle so much. This problem not only makes the boat ride unpleasant, but causes for a slower ride to control the problem and I assume it is doing damage to the engine and prop shaft as well. Please Help!!!!!

 

[MICHAEL7914]

does the vibration exist when in neutral...if so try putting screwdriver under engine mount to lift motor ever so slightly looking for reduction or more vibes[adjust mount]...if only when in gear it must be prop shaft out of balance/ i cant believe youve had such unwanted problem so long ..could be propeller..next haul out take off propshaft and get balanced...like cars the vibration only happens at certain speeds does it go away if you rev to 3k....good luck

 

[MICHAEL7914]

does the vibration exist when in neutral...if so try putting screwdriver under engine mount to lift motor ever so slightly looking for reduction or more vibes[adjust mount]...if only when in gear it must be prop shaft out of balance/ i cant believe youve had such unwanted problem so long ..could be propeller..next haul out take off propshaft and get balanced...like cars the vibration only happens at certain speeds does it go away if you rev to 3k....good luck

im assuming that p bracket is in good condition ..a worn bearing here would cause your prob..