I have a 2004 496 Mag Ho. I am having propblems with all the soot that flys up on my swim pad. It's ruining the vinyl. I can't get it clean and it only stains the left side. My boat is a 27 Fountain and have already had one cover replaced due to the soot stain from this motor. Anybody have any ideas to clean the motor and the pad?

You may want to have a Merc Mechanic check the engine out. What octane gas are you running? If you run a higher octane than called for it could be one of the causes of the soot.
Dan

Only 87!

I have twin 496 HO's and had the same soot problem during the first 20 hours. I have notice alot less soot after the 20 hours.

Mine has about 27 hrs and still is not letting up with the soot. Had local dealer call about the problem today and Mercury is sending me a leaned out computer to fix the soot problem. Will post update after this weekend on the new ecm.

Hey Alli,or should I call you "oil slick" now
Make sure you take all the old stuff off first before putting on the new computer

I don't know what you have tried to clean it with but I have had extremely good luck with "starbrite black streak remover", you can get it at any boat store. You may have to use a soft brush on the vinyl to get in the cracks. Could be a quick compromise.