[geezer#99]

Let’s correct your language first!
You’re need to learn how to read your tach
Drop a zero from your numbers.
It idles at 750, not 7500.
And you kept it running at 1250, not 12500.
Now with that cleared up let’s get to your problem.
You’ve got a flooding problem in your carb.
Causes can be trash in the needle/seat or a sunk float.
You’ll need to open up the carb to check.
You likely need to rebuild the carb you have or replace it with a rebuilt one.
A rebuilt carb can cost 200 to 500 bucks plus labor to replace it.

And welcome to the forum!