That is a 1995 model
It's a Mercury Mariner (there were Yamaha Mariner models - made exclusively for Merc, but not this one).
The single cylinder 4 and 5 horse models built in the mid 1990's (may) have been built by Tohatsu (who now builds every Merc motor below 40 horses).
I have never personally seen one of these models (other than in a showroom), so can't give you any first hand account.
As long as you don't expect too much out of it - it's only 4 horses after all - could use on a square back canoe, as a in/out of harbour ("Canadian" harbours have a "u" in them
) on a sailboat or as a trolling motor on a 14/15 footer that wasn't too heavy, you should be happy with it.