Just spent ten days in the Keys and engines ran great but I noticed after running about 3800-4200 RPM's for a half hour and then turning the engines off, they would spit out what looked like a carbon deposit upon restarting the engines. I bought the boat used with about 400 hours and had both engines serviced immediately. I use ring free each fill up and the engines run great but the carbon spit concerns me. Anybody have any insights?
