Identifying my Yamaha outboard

[pwehking]

Hi Folks,

Sorry if this question has come up before but here goes. I just bought a used boat with what I think is a 25hp outboard. It has a Yamaha logo plate on the cowling and yamaha identification plate on the transom clamp. I would like to know what year motor this is, get a manual and then parts for it but Yamaha dealers nor I seem to able to identify what this thing is. Here is what is on the identification plate.

Yamaha 25B
664 L 31793

Can you please help me find the right manual for this motor and info that describes what I have? Thanks!!!

[boats.net]

I don't have any information on that model.

[almetelo]

Hi!

All I can tell you is that motor model have been produced between 1974 and 1979.

Maybe someone can help you with the exact year.

Good luck