In order to find the year model of a Mercury outboard, you will need to know both the engine serial number, and the horsepower rating.
i have a mercury outboard motor the serial# is G034632
How old is my Kiekhaefer Mercury 7.5 boat motor Serial number 3374590
Contact your local Mercury Dealership they can tell you everything about the motor with a good serial number.
what year is this mercury outboard motor serial number OB362432
1986
On your motor mount
how old is my mercery 25 hp motor with serial number 9526046
In order to answer this question, the horsepower rating of the motor has to be known. Mercury outboards use the serial number, and horsepower, to determine year model.
1966
67
It is a 1996
1972