Yamaha 40 hp Model number

[Cabbarus]

Hello there;

I salute you all as I entered the forum newly.

So I have bought an old yamaha outboard last month and am just qurious about its model year and the shaft length as I have to buy some sphare parts.

The serial number on the bracket is 6H4- -003177, I can not read the letter in middle as it wiped off :/. Can anyone tell me the model year and the abbreviations so that I can find some parts

[boats.net]

Not without the middle letter.