What is the year of your champion blue ribbon boat motor serial number 4k307004?

To determine the year of a champion blue ribbon boat motor with the serial number 4K307004, you typically need to refer to the manufacturer's specific serial number lookup or database. Generally, the first letter or digit can indicate the year of manufacture, but without more context or access to those resources, I can't provide the exact year. You may want to contact the manufacturer or check their website for detailed information regarding serial numbers.