Brakes can be added many different ways. Pictures from you will help us help you on that subject. Morning sounds good!
As for your throttle issue, do you just quickly twist the throttle to wide open position straight from an idle or do you smoothly roll it on?
If you quickly twist it, these carburetors can take a few moments to catch up with that kind of demand. They do not have an accelerator pump. For the most part, they do not respond well like a motorcycle carb can.
"It's a chinagirl. It's a sometimes fun little engine that often will break your heart. It's disposable.
Does not come with a fortune cookie."