Hello, I have the stock Fountain mufflers on my 29. Looks like they have an average amount of carbon build-up inside. Do they require any maintenance? Should I remove and run some solvent through them to knock off some of the carbon?

Also, what do you use to seal up the space between them and the transom?

Also mufflers on boats are a new concept to me. How loud are the 525s w/o them?

Thanks.

ttt