Gidday,i am trying to find out the year of my 50 h power mercury blue band . The serial number I have is 8016593 and I am looking for both the inner and outer wiring harnesses

Hello, Melodie -

Perhaps the information here:
https://www.perfprotech.com/blog/marine-outboard-motors/how-to-find-your-mercury-marine-outboard-motor-serial-number-number
and here:
https://www.perfprotech.com/blog/articles/mercruiser-serial-numbers#
will help you locate the serial number.

Best wishes.

Locate the serial number plate by looking on your motor's transom bracket; the plate will have "Mercury Marine" written on the top. The serial number is the top number on the plate. The number directly beneath this is the year it was manufactured.
The year will be determined by the number of cylinders,,,
A 4 cyl. is a 1986 .
75 - 4 Cyl. 1986 ELPTO, ELO A197882 - B249479 = U.S. Serial Numbers A70708 = Canadian serial numbers

Does this help?
Locate the serial number plate by looking on your motor's transom bracket; the plate will have "Mercury Marine" written on the top. The serial number is the top number on the plate. The number directly beneath this is the year it was manufactured.

From everything I can find, yours is a 1986 model

Product Line Year H.P. Model Number Model Description MERCURY 1986 45 1045776 45/50 HP

cant be a 100% sure of this
there was also a model 25ss that was 20hp rated no serial numbers available but was manufactured between 1977-79
Merc 200 20 5606492 & Up 1980-81

with out information as to size, hp, band color on the cover, serial number or photo , no one will be able to answer that question
you can go google and type in--- identifying mercury outboard models and types and power ranges --
there are sites that I found quite some time ago from mercury that was pretty good and if you have a serial number and horse power , you may get the answer
of course you could always take it in to a service dealer and have it identified

According to i-Boats, "Nothing in the Mercury Mariner Outboard engine model numbers or serial numbers provides year information directly.
The first serial number sold in a year becomes the beginning serial number. Serial numbers between that year's beginning serial number and the next fall into the same year. Search for your engine horsepower on the Mercury Mariner serial number year chart located here to find the beginning serial number for the range that includes your engine." Your other option is to take the serial number to an authorized Merc marine eager and they can look it up for you.

There is no data included in the serial number that gives info of what year the engine was made. You can, however look up the number here, and that will tell you the year of manufactor.

http://www.iboats.com/basics/serial_number_year.html#mercury

Mid 70s