25hp Mariner/Yamaha??Year model-Help

[cypressdweller]

I have a 25hp mariner electric start tiller and don't know the year of it! can anyone help? The Id tag is gone but this # is on motor housing under starter- 21999682 also on a silver freeze type plug under coils was D059497 with BIG "W" under it! The Starter motor has 50-90983A1 (p/n)?? with 12-04-90 stamped on it! Maybe a 1990 model? Help please!

[boats.net]

The D059497 is the serial number, it is a 1991 model.