Looks like late 1980s. I had a 1988 Johnson 2.5hp with the same basic shape and throttle arrangement. It came in other flavors, too. Check the BRP website's parts listings and you might be able to narrow it down by looking at cowling parts diagrams, etc.
It's at: http://epc.brp.com/login.aspx?ReturnUrl=/default.aspx?brands=ej&lang=E&brands=ej&lang=E
- Scott