1991 - the "EI" in the model number tells the year. E = 9 and I =1.
An Evinrude outboard, model number E185TXCRS would be a 1984 model, 185 hp.
An Evinrude outboard, model number 35853R, would be a 1978 model, 35 hp.
An 85 hp Evinrude, model number "85"093D, would be a 1970 year model. An Evinrude model number beginning with 35, would be a 35 hp engine.
A 70 hp Evinrude outboard, model number E70ELCO, would be a 1985 year model.
An Evinrude model E4RDHSR would be a 2004, 4 hp.
An 18 hp Evinrude outboard, model 18202 would be a 1972 year model.
Model number 6303, would be a 1973 year model, 6hp Evinrude outboard.
A 15 hp Evinrude outboard, model number E15BACEC, would be a 1989 year model.
A 15 hp Evinrude outboard, model number 154040 would be a 1974 year model.
A 25 hp Evinrude outboard, model number E25TECUR, would be a 1987 year model.
In order to determine the year of manufacture for an Evinrude or Johnson outboard, you will need to know the engine model number.
Model number E20CRLCTE, would be a 1983 model, 20 hp Evinrude rope start.