Sorry it may be a 1982 if you go by this example i found below.
Imbedded in the model number is the Make, horsepower and year of the engine.
If your model number is J200TLCOS your engine is a 1985 200hpJohnson engine.
The first Letter corresponds to the first letter of the make of your engine.
The next numbers are the engine hp.
The second to last two letters correspond to the year listed in the chart below.
1980(CS) 1981(CI) 1982(CN) 1983(CT) 1984(CR) 1985(CO)
1986(CD) 1987(CU) 1988(CC) 1989(CE) 1990(ES) 1991(EI)
1992(EN) 1993(ET) 1994(ER) 1995(EO) 1996(ED) 1997(EU)
1998(EC) 1999(EE) 2000(SS) 2001(SI)