Evinrude outboard motors have an identifier label, also known as a serial number label, located on the transom. This label includes the model number of the motor. Each part of the model number tells a different detail about that motor. The label also tells the month and year of production.
The model number alone tells the story of the each particular motor. The model number contains a code to determine the style of the motor (Johnson, Evinrude, Commercial, etc.), the horsepower, the length and the model year. There is also a code in the model number for other design features, such as whether the motor is a rope start or an electric start motor. This code is explained in Evinrude's Model Number Designation Guide.
The designation guide shows that the model numbers vary depending upon the year of manufacture. Motors manufactured from 1980 through 1998 included seven variations. The model numbers of motors from this time period include a prefix telling which variation each motor is. From 1999 to present, the prefix has been dropped from the model number, but an identifier for number of cylinders has been added.
A free copy of the Model Number Designation Guide can be found in Evinrude's online store. Check the menu line across the top of the page and click on Model Year Guide to open a PDF printable version of the guide.