I have heard that the large OS carb does wonders for the power output of this engine but I have never tried it. I like the easy starting and extremely low and reliable idle that the stock carb gives.
You pays yourt money and you takes your chance.
The big carb route does sound tempting though, my Bingo is just kind of a big lazy dog, friendly and easy to get along with.
By the way, when hand starting the big ST, be sure to wear a welders glove or more; they can bite real bad.
Mine actually has this bad habit of starting backwards. I thought I got rid of that problem when I graduated from baby bees.
Peter