Your engine looks pretty much the same as mine, and your prop number looks pretty similar although mine is: 48 73132 12.
The last number "12" is the pitch as yam man pointed out as i had a 10 before. But not exactly sure what the other numbers mean
Mine is a 13 spline 10 3/4 inch if that is any help. I also got the last one on ebay for £27 in really good condition.