Locate a silver or gray metal plate over the muffler of the engine. The plate will have a series of numbers and letters printed on it. The first set indicates the model, the second the type and the third the motor code. You may need a flashlight to see the numbering and lettering. Write down the first set of numbers and letters.
Visit the "Support" section of the Snapper mower website.
Type in the six-digit model number, along with any letters, that you noted in Step 1 under the heading "Enter Model Number."
Click on the associated PDF file link that appears to view your mower's manual. Look through the first few pages of the manual to locate the year the engine was made. In some cases it may also give you the month.