I replacedmy factory radio with Standard Horizon 1600. It is DSC compatible. Works great. I got an MMSI # so I am AIS enabled.
Also got to mount in a much better location so I could hear whle underway. Will cover up old hole with nice piece of Starboard.
I know I'm late to this post. 100% certain it loose springs on the pressure plates. I had exact same issue and got it fixed. Problem all gone. Wasn't cheap as both motors needed to be pulled
I pulled all the carpet out of my 33-0 and replaced it with Lonsal (teal an holly) Looks greak-what a great upgrade. Also redid my steps with 1 inch thick teak . Mixed in some sand with a clear coat. Also a great improvement
Sorry-No pics. Boat is put away for the winter. Its is a non skid surface. Almost impossible to damage. I got the teak and holly look. Huge improvement from carpet both functionally and appearance. One of the better changes I have done
I used a similar product to vinylteak called Lonseal. It is a marine vinyl which is much heavier duty then the Home depot version. I did my 330 for approx $700. Turned out GREAT.
One simple fix is to make sure your back flame arrester is clean, When these are dirty and clogged your air mix will be off and your performance will suffer.
I had the pleasure of changing the plates in both my motors (7.4's w/Hurth transmissions). Out the door it was $5k, Pretty steep but better than buying new trannies. Sound is gone and motors are running well
I think I may have the same problem. Low RPM load transmission noise that goes away at 1000 RPMs.
My Sea Ray mechanic thinks its the pressure plates which are held on by springs. The springs have started to fail so when not under load it vibrates like hell. As soon as a load is put on motors...