The next to last two number indicate the year of the motor using this code<br /><br />I N T R O D U C E S<br />1 2 3 4 5 6 7 8 9 0<br /><br />The other numbers indicate thinks like electric start, tilt/trim, shaft length...etc but I not what yours mean.
The second to last two letters indicate the year. In you cse the "ES" and from andy's post that would be a 1990. the first 2 letters after the hp describes the motor option. I would assume that "PL" probably stands for power trim & tilt and electric start but am not 100 % sure. the laster letter doesn't really mean anything. it's just the model run if I'm correct.
