No serial number = no way to answer.
An 80 hp, Mercury outboard, serial number 3054480, would be a 1971 year model.
An 80 hp Mercury outboard, serial number 6288030 is a 1983 year model.
An 80 hp Mercury outboard, serial number 6304884 is a 1983 year model.
An 80 hp Mercury outboard, serial number 7206568 would be a 1983 year model.
An 80 hp Mercury outboard, serial number 3055133, would be a 1971 year model.
An 80 hp Mercury outboard, serial number 3057894, is a 1971 year model.
An 80 hp Mercury outboard, serial number 2561812 would be a 1969 year model.
how can i tell the year model of a Yamaha 80 dirt bike serial number 367-230432
Serial number is on the frame.
The serial number goes beyond published data. You will need to call Colt.
1987