Could be something other than the carb.
You did replace it with another Nikki?
or a knock off Look alike...
It would be a lot less headache trying to find out what's causing it not running right
than trying to make another work.
Its a knock off I'm in the process of rebuilding the original Nikki .
I just never did like a none adjustable carb that's why i want to try and replace it with a different style
I am a tinkerer and was just seeing if I might be able to replace with better carb
Well a carb is a carb is a carb
So there is no reason why you can not put another one on your engine.
You could fit a 4 barrel Holly if you really want to
However you will need to make up an adapter plate and then lengthen the control rods.
If you like to tinker then go ahead but it won't be cheap.
If you want to see what might be available as a bolt on then have a look at the racing mower specialist supply shops.
As you go up in grades then special carbs are permitted.
Almost any motorcycle carb can be made to fit or if you want to spend money there are lots of bolt on Tillotsens.
However you will be breaking EPA regulations so could be subject harsh treatment from narrow minded enforcement officers who really believe they are saving life on the planet.
I want to thank you all for your ideas.I kind of figured out that it would be a real hard mod. But i thought i would ask cause you never know.
I may try something this summer to see if i can get something to work. If i get it done I'll be sure to share it with you all