Step 1 · Look for the data tag on the Murray lawn mower. These tags are found in the rear of the mower or under the seat of riding lawn mowers, or in the center of the deck of push mowers. · Step 2 · Identify the four digits after "Date Code." · Step 3 · Interpret the four digits to figure out the year of the Murray mower. The year the mower was manufactured is represented as the first digit, and the day of the year it was produced is represented by the last three digits. For example, if the date code is "4156," the mower was produced in 2004, on the 156th day of the year. The date code could also indicate 1994. If you are unsure if your mower is that old, go to the next step. · Step 4 · Find the model number located on the data tag. Pre-2001 Murray mowers have five-digit model numbers followed by a dash and a single-digit number. Post-2001 models have a five- or six-digit model number with no dash. If the model number has a dash, the date code, for example, will indicate 1994 rather than 2004. Answer from brandon k on ifixit.com