Need year for 7.5hp Outboard

[rs_dearment]

I have a Sears and Roebuck model number 571.58761 ser # 761.4741 7.5Hp. I would like to find out what the year it was made and what the fuel mixture should be.. Ive seen most people use 50-1, I just want to make sure so I dont burn it up..<br /><br />I greatly appreciate any help thats givin