Engine year?

[Threeespot]

Buying a pontoon boat. Totally forgot to grab numbers off the engine. Any idead and any info about this engine is well appreciated.
TIA

 

[racerone]

Looks to be a Yamaha to me.

 

[fitz73222]

I'm going with 1977-1981, we sold them during those years. Long stroke, lopey idle, but propped right, were screamers on a light V bottom skiff. Light and fast. Yamaha/Merc clone.