Good Morning,
I believe that is the code number the model number should have six digits & should be above or below the number you posted.
If you can find the model number I have a B&S repair manual that B&S sent me for free (it shows how all the carb/gov linkages are set) as I was having this problem with my 7.5Hp intek snow that I had bought for my 78 Toro snowblower.
Having said this if your is like mine as mine was doing the same as yours I found that I had to replace both springs that ran off the governor lever. My model number is 12D413
If you can find this number I'll look it up & send you the page from the service manual it tells & shows everything.