I am new to Mercury's myself, but so far I have found that parts are by serial number of motor, not model and year. However, there is a link on here to a chart that helps determine the year based on the serial number range that you motor falls in. If you have the 9.8hp 2 cylinder Mercury 110, then looks like you have a 1966. And if you have a 110hp 6 cylinder Mercury, it coincidentally is still a 1966.